MCAT question bank

A gas is initially at a pressure of P1 and at a volume of V1. What is the volume of the gas if the pressure suddenly changes to P2? a) P1V1/P2 b) P1P2/V1 c) P2V1/P1 d) P2/P1V1

a)

A krypton fluoride laser can emit light in brief pulses of only 4 nanoseconds. Given the velocity of light in a vacuum is 3 x 108 m/s, how long is each pulse of light if emitted underwater? Note the index of refraction of water is 1.33. a) 90 cm b) 1.2 m c) 1.6 m d) 2.1 m

a)

An Bronsted-Lowry acid can be defined as: a) a substance which is capable of donating hydrogen ions. b) a substance which acts as an electron pair acceptor. c) a substance which acts as an electron pair donor. d) a substance which may act as both an acid as well as a base.

a)

An object is placed in front of a convex lens at a distance half the length of the focal length. The image produced of the object would be: a) virtual and upright. b) virtual and inverted. c) real and upright. d) real and inverted.

a)

As a receiver moves away from a source of sound, the energy of the sound wave at a given distance decreases in proportion to which of the following? a) the surface area of a sphere b) the volume of a sphere c) the circumference of a circle d) the the surface area of a cube

a)

At which pH could the equivalence point of a weak base titrated with hydrochloric acid be reached? a) 5.6 b) 7 c) 7.5 d) None of the above

a)

Electromagnetic radiation is a a) transverse wave only b) longitudinal wave only c) longitudinal and transverse wave d) longitudinal or transverse wave

a)

Given 1 mole of CH4, which of the following relationships is true, given P is the pressure, V is the volume, R is the ideal gas constant, and T is the absolute temperature? a) PV/RT = 1 b) PR/T = V c) PT/R = V d) RV/PT = 1

a)

Given gravitational force as F = G*M*m/r2 where G is the gravitational constant, M is the mass of one object, m is the mass of the other object, and r is the distance between their center of masses, what is the expression for gravitational acceleration of an object at distance r? a) G*M/r2 b) M*m/r2 c) G*M*m/r d) G*M*m*r2

a)

In the reaction below, which species acts as the reducing agent? 2 As (s) + 3 Cl2 (g) → 2 AsCl3 a) As b) Cl2 c) AsCl3 d) The reaction depicted is not a redox reaction.

a)

The diopter has which of the following units? a) 1/length b) 1/length2 c) length d) length2

a)

The focal length of concave mirror refers to a) a distance away from the mirror where parallel rays will converge b) a value double the radius of curvature c) whether a mirror is concave or convex d) a value which increases with increasing convergent strength of the mirror

a)

The lone pairs on the oxygen atom in H2O allow it to act as which of the following when accepting a proton to form H3O+? a) Lewis base b) Lewis acid c) Arrhenius base d) Arrhenius acid

a)

What is the kinetic energy of a 0.1kg projectile traveling at 60ms? a) 180J b) 18J c) 70J d) 150J e) 80J

a)

Which of the following colors has the highest energy? a) Blue b) Green c) Yellow d) Red

a)

Which of the following compounds contains the lowest carbon percent composition? a) methane b) ethane c) propane d) butane

a)

Which of the following depicts the units of the coefficient of static friction for a block resting on the ground? a) unitless b) 1/mass c) 1/mass*distance d) distance/mass

a)

Which of the following gases most likely has the highest heat capacity? a) CCl4 b) BH3 c) Xe d) O2

a)

Which of the following holds true regarding escape velocity with respect to Earth? a) it is not proportional to the mass of the individual object achieving escape velocity b) it is not proportional to the mass of Earth c) it is not proportional to the radius of Earth d) it refers to the speed where an object will remain in orbit around a body and will not drift closer or further from the central object of mass

a)

Which of the following is a true statement regarding ideal gases? a) The volume of an ideal gas is less than the volume of the equivalent real gas. b) The pressure of an ideal gas is less than the volume of the equivalent real gas. c) The size of molecules is included in calculations involving ideal gases. d) The relationship where increased volume results in decreased pressure is only true for ideal gases.

a)

Which substance can be classified as an Arrhenius acid? a) HCl b) NaCl c) LiOH d) KOH

a)

ncreased temperature serves to: a) increase the reaction rate for a reaction. b) increase activation energy for a reaction. c) decrease activation energy for a reaction. d) maintain the same reaction rate for a reaction

a)

Which of the following options demonstrates the correct order of embryogenesis? a) Fertilization → Cleavage → Blastula formation → Gastrulation b) Fertilization → Blastula formation → Cleavage → Gastrulation c) Fertilization → Blastula formation → Gastrulation → Cleavage d) Fertilization → Cleavage → Gastrulation → Blastula formation

a) 1. fertilization: the joining of an egg and sperm 2. Cleavage: early cell division in an embryo before a specific structure is formed 3. blastula formation: the cells of the embryo form a hollow structure filled with fluid 4. gastrulation: the cells in the embryo migrate to form the three germ layers; the hole with fluid formed during the blastula stage is now filled with cells

Two epimers are studied in a laboratory and their respective stereocenters are reviewed. How many stereocenters may differ between the two molecules? I. one II. two III. three or more a) I only b) I and II only c) II only d) I, II, and III

a) Epimers are stereoisomers that differ at only a single stereocenter, thus (A) is the correct answer.

Gastrulation is followed directly by: a) nerulation b) fertilization c) morulation d) morphogenesis

a) Nerulation is the formation of the neural tube and occurs just after gastrulation.

How many proton NMR signals would be expected for 3-pentanone, neglecting peak splitting? a) 1 b) 2 c) 4 d) 10

b) 3-pentanone (shown below) has a total of 10 hydrogen atoms but electronically equivalent hydrogen atoms will appear as as single peaks. Since both methyl groups are identical and both CH2 groups are identical but the methyl groups are different from the CH2 groups, the NMR spectrum will show two different peaks.

A catalyst would change which of the following? A. Enthalpy B. Activation energy C. Entropy D. Change of Enthalpy

b) A catalyst lowers the activation energy, Ea, of a reaction.

In humans, the fusion of the nuclei of two functional gametes results in the formation of a a) monoploid cell b) zygote c) cotyledon d) polyploid cell

b) A monoploid cell is a cell with half the normal number of chromosomes, these are gametes. Fusing two of these together restores the normal number of chromosomes in fertilization. A cotyledon is part of a seed and a polyploid cell is a cell with more than the normal number of chromosomes.

A species of desert plant secretes a chemical into the surrounding soil that kills seeds from any other species of plant that attempts to germinate in that area. What is this an example of? A. Commensalism B. Allelopathy C. Exploitation competition D. Apparent competition

b) Allelopathy is type of INTERFERENCE competition, where the establishment of other individuals who would compete for a mutual resource is prevented, in this case using a toxic chemical. Intraspecific competition occurs when competition occurs within the same species; in this case the plant is competing with all the other species of plants in the area.

Which of the following can NOT be classified as eukaryotic organisms? a) Plants b) Archaea c) Protists d) Fungi

b) Archaea are a domain of single-celled microorganisms, and because they have no cell nucleus (or any other organelles inside their cells), they are NOT classified as eukaryotic organisms.

An EMT sees himself as a bit of a rebel, but is highly sociable and is able to keep calm in an emergency. This person would likely score in the lower range of which of the following traits? a. Psychoticism b. Neuroticism c. Extraversion d. Conscientiousness

b) As a rebel and a sociable person, this individual would score highly on both psychoticism and extraversion, respectively. Neuroticism is associated with high emotional arousal in stressful situations, so being able to keep calm in an emergency is a sign of low neuroticism. Conscientiousness, a trait associated with being hardworking and organized instead of impulsive, is not described by the question stem

An athlete is trying to prepare for a long day of physical activity and eats a high-protein meal in the morning. During their exercise, which of the following is most likely true? a) Their body does not fully digest the protein until later in the day b) The athlete will require more oxygen inhalation to digest the meal c) Their heart rate will decrease as the day goes on d) Their muscles will fatigue after metabolizing the protein diet e) They will not get as much energy as if they had consumed a beverage with electrolytes

a) exercise can induce the release of corticoids which stimulate the sympathetic nervous system. This initiation will divert the body's resources and blood flows away from the digestive system, and toward the muscles that the athlete is engaging. As such, the meal will take a long period of time to digest

The area of the brain through which conscious and unconscious sensory signals travel is known as the: a) Diencephalon b) Brain stem c) Cerebellum d) Cerebrum

a) The diencephalon is home to the epithalamus, thalamus, and the hypothalamus. It integrates sensory inputs and motor commands.

A polar solid matrix is used for thin layer chromatography. If a nonpolar compound is spotted onto the solid matrix, compare the speed of travel of the compound in the following solvents, from slowest to fastest. I. diethyl ether II. hexane III. methanol a) III, I, II b) I, II, III c) II, I, III d) III, II, I

a) Because the solid phase is polar, the compound spotted onto it will spend less time with the matrix than with a nonpolar solvent. Therefore the question is the same as: order the solvents by decreasing polarity. Methanol is the most polar, followed by diethyl ether, and then hexane; III, I, II.

The van der Waals equation suggests the relationship that: a) the larger the volume of a gas molecule, the less the gas follows the ideal gas law. b) the faster a molecule is traveling, the higher its temperature. c) all compounds have a triple point, i.e. a temperature-pressure combination where solid, liquid, and gas phases all exist d) magnetic fields run in perpendicular to electric fields.

a) The van der Waals equation attempts to describe gases and their variance from ideal gas behavior. Generally, gases follow the ideal gas equation less with increasing gas molecule volume

Which angle is common to tetrahedral molecules? A. 109.5° B. 120° C. 60° D. 90°

a) Tetrahedral geometry has three-dimensional placement with atoms positioned at 109.5° to each other. Trigonal planar molecules have angles of 120°, interior angles of 60° are associated with strained cyclopropanes bonding, 90° with cyclobutanes and 180° for alkynes.

Which ion channels are responsible for maintaining the resting membrane potential? a) Ungated channels b) Voltage-gated channels c) Ligand-gated channels d) No ion channels are involved in maintenance of the resting membrane potential.

a) The resting membrane potential is displayed by cells that are not actively involved in signal transduction. Ungated or "leak" channels permit limited free flow of ions, while the sodium-potassium pump is also active and corrects for this leakage. Ligand-gated and voltage-gated channels are involved in cell signaling and in the pacemaker potentials of certain cells, but cause deviation from—not maintenance of—the resting membrane potential.

A battery consists of which type of cells? a) electrolytic b) electrochemical c) electroplating d) electromagnetic

b)

A gaseous hydrocarbon at STP occupies 44.8 L of space. If it is measured that there is 116 g of the gas, what is the hydrocarbon? a)C3H8 b) C4H10 c) C5H12 d) C5H10

b)

As a ray of light passes from one medium into another, the angle of the ray of light changes. Assuming no dispersion, if the wavelength of that ray of light is increased, the angle of refraction will a) decrease. b) remain the same. c) increase. d) increase or decrease, depending on whether there is an increase or decrease in the index of refraction.

b)

Which of the following is the approximate percent composition by mass of oxygen in chromium (IV) oxide? a) 30% b) 40% c) 50% d) 60%

b)

Which of the following is true regarding concentration cells? a) the cells operate in absence of a salt bridge b) the Nernst equation can be used to measure the potential for these cells c) they are a subtype of electrolytic cells d) electrodes for each half-cell are composed of different compounds

b)

Which of the following is true when the pH of a solution is equal to the pKa of a monoprotic acid in the solution? a) The acid has been titrated to its equivalence point. b) 50% of the acid has been deprotonated. c) The acid has been neutralized. d) The solution is neutral.

b)

Which of the following molecules contain sp3d orbitals? a) sulfur hexafluoride b) phosphorous pentachloride c) fluoromethane d) butane

b)

Which of the following salts would have the greatest freezing point depression capacity if 0.05 M were added to water? Assume total solubility of each. a) CaCl2 b) Al2(SO4)3 c) MgSO4 d) NaCl

b)

The electron configuration of Cd2+ is best described by which of the following? A. [Kr] 4s25d10 B. [Kr] 4d10 C. [Kr] 5s24d10 D. [Kr] 5s24d8

b) Cadmium in it's basic state has Configuration [Kr] 5s24d10. Positively charged cadmium (II) has lost 2 electrons. It will lose its two 5s-electrons first, making B the most reasonable answer. Answer A is illogical, as it has a higher shell number (5) for the d-electrons than the s-electrons (4). C is the correct configuration for neutral cadmium. Finally, D is incorrect because the d-electrons were removed rather than the s-electrons.

During vacuum distillation, what is the purpose of decreasing the pressure? a) to increase the boiling point b) to decrease the boiling point c) to slow down the distillation d) to stop the distillation once completed

b) Decreasing the pressure of a system decreases the boiling point. This in turn speeds up the distillation and eliminates the need for higher temperatures.

People who are aging often get teased about their memory, but not necessarily all of it declines at the same pace. Which of the following would you expect and elderly individual to have the most trouble recalling? A. How and where they met their significant other B. A hair cut scheduled for 2 PM C. The name of the host for their favorite late night talk show D. A movie that needs to be returned while passing by the movie store on their walk E. They would have equal difficulty with all

b) Elderly individuals have the most trouble with time-based prospective memory, or in other words, remembering to do an activity at a specific time. The other forms of memory ought to generally be preserved, or at least decline less significantly than time-based prospective memory.

Which of the following laboratory techniques would allow for separation of enantiomers? a) distillation b) chiral chromatography c) electrophoresis d) affinity chromatography

b) Enantiomers have the same physical properties, thus distillation (which relies on differing volatility of substances), electrophoresis, and affinity chromatography will not work. Chiral chromatography, the only answer option left, is a viable technique however the inner-workings on this method are beyond the MCAT. Thus (B) is the correct answer.

Which of the following cells produce myelin in the central nervous system? a) Schwann cells b) Oligodendrocytes c) Astrocytes d) Microglia

b) Oligodendrocytes produce myelin in the central nervous system while Schwann cells produce myelin in the peripheral nervous system. Astrocytes support the endothelial cells that make up the blood�brain barrier, provide nutrients to nervous tissue, maintain extracellular ion balance, and help repair and a play a role in the scarring process in the brain and spinal cord following traumatic injuries. Microglia function as macrophages in the central nervous system. Thus, answer choice (B) is correct.

Which of the following compounds would be expected to travel farthest in a paper chromatography separation experiment? a) 1-propanol b) hexane c) acetone d) methanol

b) Paper chromatography involves a polar matrix (the cellulose of the paper is polar) with a nonpolar mobile phase (generally some combination of ethyl acetate and petroleum ether). As in other forms of chromatography separating compounds by polarity, the relative distance traveled (or relative elution time) will be proportional to the relative polarities. Since hexane is the least polar compound listed, it will travel fastest up the paper since it interacts more favorably with the moving mobile phase than with the stationary phase.

In a radioactive series, the nucleus of 241/95Am decays and emits an alpha particle, β- decay, and then β- decay. The final product of the series is: a) 244/91Pa b) 237/93Np c) 237/95Am d) 237/91Pa

c)

Total internal reflection: a) takes place when all light from one medium refracts as it enters a different medium. b) is an identical term to critical angle. c) takes place when light moves from a medium with higher index of refraction to a lower index of refraction. d) is only a term relevant to light traveling through water.

c)

What is the mole fraction of oxygen in the compound Ni(CO)4? a) 0.2 b) 0.37 c) 0.44 d) 0.66

c)

What is the orbital hybridization of S in SH2? a) sp b) sp2 c) sp3 d) s2p2

c)

Which of the following is not a colligative property? a) Boiling point elevation b) Freezing point depression c) Density d) Vapor pressure

c)

The basic premise of cladistics is organisms that are closely related share a common evolutionary history. The characteristics that are shared by group members and derived from their ancestors are called: A. Plesiomorphies B. Synapomorphies C. Apomorphies D. Autapomorphies

b) Plesiomorphies are characteristics that are original in the organism. While apomorhic means "derived characteristic", the prefix syn- alters the meaning to "shared derived characteristic." Using the prefix aut- causes the meaning to change to "self-derived characteristic" implying that it isn't shared by another group. Homoplasy or homoplastic characteristics are shared among groups, but weren't derived from an ancestral source.

Elephant seal males mate with multiple females each mating season, while females only have one mate each. What type of mating system is this? a) Polyandry b) Polygyny c) Monogamy d) Promiscuity

b) Polygamy involves a male having exclusive relationships with several females (polygyny) or a female having exclusive relationships with several males (polyandry), choice (A). Monogamy, choice (C), consists of exclusive mating relationships. Promiscuity, choice (D), refers to a member of one sex mating with any member of the opposite sex.

Signal detection theory is a subset of which of the following fields of psychology? a) Gestalt principles b) psychophysics c) theories of consciousness d) psychoanalysis

b) Psychophysics refers to a branch of psychology that relates physical stimuli and the perceptions and analysis of such stimuli. Signal detection theory describes how humans differentiate important stimuli from noise and unimportant stimuli. Thus is a subset of psychophysics, thus (B) is the correct answer.

A bar 8 meters long is placed on a pivot 2.0 meters from the lighter end of the bar. The center of gravity of the bar is located 2.0 meters from the heavier end. If a 500 N weight on the light end balances the bar, what must be the weight of the bar? A. 125 N B. 250 N C. 500 N D. 1000 N

b) The center of gravity occurs 4.0 m from the pivot point. At equilibrium: (2.0 m)(500 N) = (4.0 m)(w) w = ½ (500N) = 250 N

A reaction that has oxygen and hydrocarbons as the reactants and produces both carbon dioxide and water can be best characterized as what? A. Single-displacement reaction B. Double displacement reaction C. Combustion reaction D. Combination reaction E. Decomposition reaction

c) This describes combustion reactions to a t. In combustion reactions, a hydrocarbon acts as fuel when reacting with oxygen. The products are then carbon dioxide and water.

Which of the following is closest to the pH of a mixture made up of 0.1 M each formic acid (whose Ka is 1.8 x 10-4) and potassium formate? A. 0.1. B. 2. C. 4. D. 7.

c) This solution is a buffer, for which: [H+] = Ka [HFor]/[For-] = Ka pH = -log (1.8 x 10-4) = 3.7

Certain neurons have been found to have almost negligible refractory periods. What physiological property could be expected of this neuron? a) Long time points between neuronal firing b) Having very few sodium channels c) Potassium channels with the ability to close very quickly d) Lacking myelination on axons

c) To solve this problem, you must think about what causes the refractory period. After an action potential, potassium channels open to allow potassium out of the cell in order to repolarize the neuron to basal potential. These channels close quite slowly, thus what actually occurs is too much potassium flows out and the potential is actually less than basal, i.e. the neuron becomes hyperpolarized. If potassium channels were capable of closing very quickly, such a refractory period would likely not occur because the hyperpolarization of the neuron would not be observed.

The nuclear reaction of 2613Al → 2612Mg is an example of which of the following types of nuclear decay? a) β- decay b) alpha decay c) gamma decay d) electron capture

d)

Two cars, A and B, are moving toward one another but decelerating. During the deceleration, car A sounds its horn at a frequency of 400 Hz. Which of the following is most likely the frequency heard by car B? a) 325 Hz b) 375 Hz c) 400 Hz d) 450 Hz

d)

Which is a feature of gamma rays? a) They have the longest wavelength in the electromagnetic spectrum b) they have the least energy in the electromagnetic spectrum c) They are emitted by electrons from outside the nucleus d) they can kill cells

d)

Which occurrence is possible with light waves but impossible with sound waves? a) Interference b) Doppler effect c) Refraction d) Polarization

d)

Which of the following has the highest boiling point? a) 0.5 M NaCl b) 1.0 M Glucose c) 0.5 M Glucose d) 1.0 M NaCl

d)

Which of the following is NOT characteristic of alkanes? a) Low reactivity b) Composed exclusively of hydrogen and carbon atoms in a formula proportional to CnH2n+2 c) Occur naturally in the environment d) Characterized by a high number of pi bonds

d)

Which of the following provides a plausible explanation for why resistance of resistors add when they are in series rather than in parallel? a) Total resistance of a set of resistors has no relation to the length of the resistor, thus it is intuitive that adding in series is most accurate for adding resistors b) Increased area of a resistor increases its resistance, and adding resistors in series functionally increases cross-sectional area c) Resistors in parallel increase distance that current must travel, thus it is intuitive that this would decrease resistance (and resistors in series would add resistance) d) Increased length of a resistor increases its resistance and adding resistors in series is functionally equivalent to adding length to the resistor

d)

You are given three capacitors of capacitance X. If you are allowed to place the capacitors in a circuit in any fashion, how many different effective capacitances can you get? a) 1 b) 2 c) 3 d) 4

d)

Zn + 2HCl → ZnCl2 + H2 What volume of gas is produced by the reaction above if 2 moles of HCl are used with excess Zn at STP? a) 1 L b) 2 L c) 11.2 L d) 22.4 L

d)

If the sum of all the forces acting on a moving object is zero, the object will: A. decelerate and stop. B. accelerate uniformly. C. change the direction of its motion. D. continue moving with constant velocity.

d) For something to change direction or accelerate there must be a net force acting on it (Newton's 2nd Law). Also, Newton's 1st Law states that an object in motion will stay in motion at constant velocity (a form of inertia) unless acted upon by a net (an unbalanced) force.

Gamma rays are electromagnetic radiation which involves the: a) release of neutrons. b) release of protons. c) release of electrons. d) release of photons.

d) Gamma radiation involves photon release, or simply the release of energy. Neither protons, electrons, or neutrons are released. Thus (D) is the correct.

Which of the following physiologic changes would result in a more rapid heart rate? a) decreased SA node activity b) decreased AV node activity c) going from a walking position to sitting d) decreased parasympathetic activity of the vagus nerve

d) The vagus nerve provides parasympathetic innervation to the heart and serves to decrease heart rate. Decreased activity of the vagus nerve would result in a more rapid heart rate, thus (D) is the correct answer.

a medical student is feeling a high level of stress due to upcoming exams and pressure from his family to engage in activities at home. He chooses to go to the gym for a workout to help himself relax. This workout is which type of stress? a) hassle b) frustration c) distress d) eustress

d) a positive stressor creates eustress. Because working out is used to relax, it is considered a eustress. Hassle, choice A, and frustration, choice B, are both types of distress, choice C, or negative stressors

What enzyme is required for transcription of mRNA in eukaryotes? a) DNA polymerase b) RNA polymerase III c) RNA polymerase II d) RNA polymerase I

c) RNA polymerase II is required for transcription of mRNA, snRNA, and miRNA. Alternatively, RNA polymerase I transcribes some rRNA and RNA polymerase III transcribes tRNA, some rRNA, and other small RNAs. DNA polymerase is required for DNA replication but does not play a role in transcription

Which of the following neurotransmitters is associated with both schizophrenia and Parkinson's disease? a) GABA b) Serotonin c) Dopamine d) Enkephalins

c) Schizophrenia is associated with high levels of dopamine, or high sensitivity to dopamine. Parkinson's disease is associated with destruction of the dopaminergic neurons in the basal ganglia.

Which statement below about recrystallization is NOT correct? A. The method relies on the fact that solids are more soluble in a cold solvent than they are in the same amount of hot solvent. B. Precipitation is initiated by adding a seed crystal of the compound being purified. C. Scratching the side of the vessel at the air/solution interface can induce crystal nucleation. D. Slowly cooling the solution promotes precipitation of the compound.

This statement is reversed: The process of recrystallization involves dissolution of the solid in appropriate solvent at a high temperature and the subsequent re-formation of the crystals upon cooling, so that any impurities remain in solution.

Which of the following is not a characteristic of prokaryotes? a) Presence of ribosomes b) Presence of mitochondria c) Presence of a cell wall d) Circular chromosome

b) prokaryotes do not have membrane-bound organelles, such as the nucleus or mitochondria. In fact, endosymbiotic theory suggests that mitochondria evolved from symbiotic prokaryotic relationships. Prokaryotes are often associated with all of the other characteristics listed

A 55kg individual sits at the left end of a 2m seesaw and a 75kg individual sits on the right end. Where is the center of mass for this system? a) 0.8 m from the left of the seesaw b) 1 m from the left of the seesaw c) 1.2 m from the left of the seesaw d) 1.4 m from the left of the seesaw

c)

A chemical reaction occurs within a sealed container. If the moles of gas double and the volume is halved, what is the magnitude of the pressure assuming temperature remains constant? a) P b) 2P c) 4P d) 8P

c)

A galvanic cell is set-up between an Ag-AgCl electrode and standard hydrogen electrode. Some standard reduction potentials are provided. What is the potential across in this electrochemical cell? 2H+ + 2e- → H2 (E° = 0.00 V) 2H2O + 2e- → H2 + 2OH- (E° = -0.83 V) Ag+ + e- → Ag (E° = 0.80 V) AgCl + e- → Ag + Cl- (E° = 0.22 V) a) 0.44 V b) 1.63 V c) 0.22 V d) 0.00 V

c)

A man travels to a planet that has twice the radius of the earth and twice the mass. His weight on that planet compared to his weight on earth is: a) Doubled b) Tripled c) Halved d) Quadrupled

c)

A massless tether is tied to a block and held vertically over the block. If the block masses, 5kg, how much force is required to accelerate the block upward at 2 m/s2? Assume g = 10 m/s2. a) 10 N b) 50 N c) 60 N d) 20 N

c)

A research study is developed to look at the link between alcohol use and lung cancer. A confounding variable that should be considered in this experimental design is: a) type of alcohol consumed. b) amount of alcohol consumed. c) tobacco use. d) age of lung cancer diagnosis.

c)

A researcher is attempting to excite an electron transition using light but finds that the energy supplied is too low. Which of the following could help achieve the necessary energy for the transition? a) increase the wavelength of the light b) increase the intensity of the light c) increase the frequency of the light d) increase the index of refraction

c)

A stationary object is emitting a tone of 1000 Hz while a car approaches it. If the car is also emitting a tone of 1000 Hz, and an observer on the stationary object hears a beat frequency of 10 Hz, how fast is the car moving toward the object? Assume the speed of sound in air is 350 m/s. a) 0.35 m/s b) 1.15 m/s c) 3.5 m/s d) 10 m/s

c)

A titration was performed on a weak acid of pKa 5 with an extremely strong base. On the titration curve, at which pH will the equivalence point be seen? a) Less than 7 b) 7 c) Greater than 7 d) Not enough information given

c)

A weak acid is titrated with NaOH. The equivalence point will occur at a pH a) Less than 7 b) of 7 c) Greater than 7 d) dependent on the pKa of the weak acid

c)

Which of the following events typically takes place during the S-phase of the cell life cycle? a) DNA replication b) Ceasing of cell division and replication c) Marked growth of the cell d) Division of the cell into two daughter cells

a) The S-phase of the cell cycle is responsible for DNA replication and precedes the G2-phase where the cell continues to grow and goes through various checkpoints to make sure that the cell is ready to go through mitosis. Thus (A) is the correct answer.

At 25C, a one liter sample of pure water has a vapor pressure of 18.5 torr. If 10 g of NaCl are added to the sample, the vapor pressure of the water will: A. Decrease. B. Increase. C. Remain unchanged. D. Be equal to he vapor pressure of the added NaCl.

a) The addition of a solute to a liquid always lowers the vapor pressure of the liquid.

An alkyl halide is formed with various halide R-groups. Which of the following R-groups would yield the molecule with the least likelihood of participating in an SN2 reaction? a) F b) Cl c) I d) Br

a) The atom with the tightest bound R-group would be least likely to undergo an SN2 reaction. The fluoride anion is the smallest of those listed, thus it is the most difficult to remove and would yield the lowest likelihood of participating in an SN2 reaction. Thus (A) is the correct answer.

112 g of an isotope are present at t = 0. At t = 18 minutes, 28 g of isotope remain. What is the half life of the isotope? a) 4.5 minutes b) 9 minutes c) 18 minutes d) 36 minutes

b)

250g of a solute are dissolved in 400cc of a solvent with a density of 0.6g/mL. Which of the following is the percent composition of mass of the solute in this solution? a) 25% b) 50% c) 75% d) 95%

b)

A beaker of gas contains 24 moles of A, 36 of B, and 36 of C. What is the mole fraction of compound A? a) 24 b) 0.25 c) 1/3 d) .5

b)

A buffer is made for an experiment to a pH of 7.5. The scientist realizes that the volume of the buffer is 5 mL too low, and adds 5 mL of water. What will be the pH of the subsequent solution? a) pH < 7 b) 7 < pH < 7.5 c) pH = 7.5 d) pH > 7.5

b)

A chlorine atom can form I. A single sigma bond II. Four sigma bonds and three pi bonds III. Four sigma bonds and four pi bonds a) I only b) I and II only c) III only d) I, II, and III

b)

A container at standard atmospheric pressure contains two gases, A and B. It contains 1/3 moles of gas A and 5/3 moles of gas B. Which of the following is the approximate partial pressure of gas A in the container? a) 0.1 atm b) 0.16 atm c) 0.2 atm d) 0.3 atm

b)

A gas is observed to exhibit an aggregation of its molecules into clumps of different sizes. Each clump contains 2k molecules, for some integer k, i.e. the size of clump increases by doubling. How will a clump with 2k molecules effuse out of a small hole in comparison to one molecule? a) 2k/2 times faster b) 2k/2 times slower c) 2-k/2 times faster d) 2-k/2 times slower

b)

A laboratory shines a single beam of light into a fluid at an angle of 30°. Assuming the refractive index of air is 1, and the beam of light refracts at an angle of 60°, what is the refractive index of the unknown fluid? a) √3 b) 1/√3 c) 1/2 d) 2√3

b)

A particular atom has a mass number of 104 with 64 protons. How many alpha decays are necessary to get to a mass number of 84? a) 4 b) 5 c) 10 d) 12

b)

A person is playing a piano, with a frequency of 200 Hz, directly next to another person playing the drums with a frequency of 175 Hz. What is the beat frequency of the two? a) 15 Hz b) 25 Hz c) 50 Hz d) 75 Hz

b)

A phase diagram depicts the conditions under which a substance is in its solid, liquid, or gaseous state. What are the axes of the phase diagram? a) temperature (y-axis) vs. pressure (x-axis) b) pressure (y-axis) vs. temperature (x-axis) c) temperature (y-axis) vs. vapor pressure (x-axis) d) vapor pressure (y-axis) vs. temperature (x-axis)

b)

A radioactive compound has a half life of 50 years. After how many years would 200g of this compound decay to to 3.125g? a) 250 years b) 300 years c) 350 years d) 400 years

b)

Where the interaction of two tones at 400 Hz and 405 Hz produces a beat frequency, that beat frequency is observed as a result of which of the following phenomena? a) Doppler effect b) constructive and destructive interference of the sound c) shifting of one of the tone phases to match the other d) polarization of the sound

b)

Which is a feature of a reducing agent? a) It becomes reduced b) It donates electrons to other species c) Its oxidation number decreases d) An atom with a smaller atomic radius is a better reductant

b)

Which of the following are not prokaryotic organisms? a) organism from the archaea domain b) yeast c) bacilli bacteria d) cocci bacteria

b)

Which of the following best explains the relationship between pressure and volume when a balloon is squeezed? a) At constant temperature, the pressure of a gas is directly proportional to the volume b) At constant temperature, the pressure of a gas is inversely proportional to the volume c) For an enclosed, elastic space, the relationship between pressure and volume depends on the gas being used d) At constant temperature, volume does not influence the pressure of the balloon

b)

Which of the following correctly shows the relationship between electromagnetic waves in terms of frequency? a) Radio > ultraviolet > gamma rays b) Gamma rays > ultraviolet > radio c)Radio > infrared > optical d) Gamma rays > infrared > optical

b)

Which of the following has the most positive oxidation state of carbon? a) C2H6 b) CHCl3 c) CH4 d) C2H2

b)

Which of the following is NOT an assumption made in the ideal gas law as it pertains to kinetic molecular theory? a) molecules within gases have negligible volume b) collisions between two gas molecules is inelastic c) gas particles move randomly with respect to each other d) there are no attractive or repulsive forces between molecules

b)

Which of the following is false regarding titration curves? a) when pH = pKa for an acid, there are equal protonated and deprotonated molecules b) diprotic acids can have one or two equivalence points c) as pH increases for an acid, more molecules become deprotonated d) the midpoint is the region most effective for buffering

b)

Polypeptides are molecules that contain multiple __________. a) nucleic acids b) amino acids c) lipids d) phosphates e) monosaccharides

b) polypeptides are made from individual amino acids through formation of peptide bonds monosaccharides are the fundamental units for carbohydrates while fatty acids come together to form lipids. Nucleotides and phosphates are key components of the nucleic acids, RNA and DNA

Which of the following is a primary lymphoid structure? I. Thymus II. Spleen III. Lymph node a) II and III b) I only c) I, II, and III d) III only

b) primary lymphoid tissues refer to the tissues where lymphoid cells are generated, while secondary lymphoid tissues are the functional organs of the lymphatic system lymphocytes are generated and developed in the bone marrow and thymus only. The spleen and lymph nodes are examples of secondary lymphatic organs

At immense pressures, hydrogen undergoes a phase transition to a unique state. In this state, the space between hydrogen atoms is less than their Bohr radius, meaning electron clouds overlap significantly. This overlap explains which of the following phenomena of this state of hydrogen? a) its lack of a triple point with any other state of hydrogen b) its density being lower than at STP c) its ability to conduct electricity d) its lack of color

c)

Boiling food generally takes longer at high altitude than at sea level due to the lowered boiling point at lower atmospheric pressures. The boiling temperature can be brought up to 100 °C by which of the following mechanisms? a) Reducing the amount of water being used at a given time b) Increasing the amount of heat added by the stove c) Adding salt to the water d) Reducing the amount of food solids being cooked at a given time

c)

Cu + 2Ag+ → Cu2+ + 2Ag What is the standard potential of an electrochemical cell running the reaction above given the standard half-cell potentials below? Cu2+ + 2e- → Cu +0.34 V Ag+ + e- → Ag +0.80 V a) -0.46 V b) 1.14 V c) 0.46 V d) 1.26 V

c)

Given a balloon containing N2, which of the following would double its volume? a) Reduce the temperature by a factor of 2 b) Reduce both the temperature and pressure by a factor of 2 c) Reduce the pressure by a factor of 2 d) Increase the pressure by a factor of 2

c)

Given the shapes of s-orbitals and p-orbitals, which of the following hybridized orbitals is most spherical? a) sp3 b) sp2 c) sp d) All of the above have identical spherical shape

c)

A biconvex lens can produce a virtual image if which of the following is true? a) The image is inverted. b) The object is at infinity. c) The image is formed at the focal length. d) The object is inside the focal length of the lens.

d)

A colligative property is one that: a) will not affect freezing point of solutions but will affect boiling point. b) depends only on the total number of molecules in a solution. c) has no in the properties of liquids. d) depends on the ratio of the number of solute molecules to solvent molecules.

d)

A doctor is rushing through the hospital hallway to the emergency room and is approaching a corner. In order to avoid a collision, the doctor looks at the convex safety mirror in the corner of the hallway. Describe the image in the mirror as the doctor approaches the corner. a) Real, Inverted b) Virtual, Inverted c) Real, Upright d)Virtual, Upright

d)

A light source is placed near a diverging lens. For which placement would a real image be formed? a) At the focal length b) At a distance of twice the focal length c) At a distance half the focal length d) A real image can never be formed

d)

A particular radioisotope decays in the following order: alpha, beta, beta, alpha, gamma. How many neutrons have been emitted during the series of decays? a) 0 b) 1 c) 2 d) 4

d)

A porous balloon allowing gas exchange is filled with an equal molar amount of hydrogen gas and oxygen. Which of the following statements is true after after some time? a) The mole fraction of hydrogen in the balloon is greater than 0.5 b) Oxygen leaves the hole at a faster rate than hydrogen c) The mole fraction of hydrogen outside of the balloon is greater than 0.5 d) The mole fraction of oxygen in the balloon is greater than 0.5

d)

A sound wave travels from a dense medium to a less dense medium. Which of the following will hold true after the wave enters the less dense medium? a) The wave will reflect in an inverted fashion b) Frequency of the wave will increase c) The wave will refract into the less dense medium in an inverted fashion d) None of the above

d)

A student looks into a mirror and sees her reflection is upright. Which of the following mirrors could she be observing? I. concave mirror II. convex mirror III. flat mirror a) III only b) II and III only c) I and II only d) I, II, and III

d)

A vibrating string is behaving like a standing wave with nodes at the ends and 3 antinodes. The string is 150 cm long and the wave travels at 20 m/s. What is the string vibration wavelength and frequency? a) 0.75 m, 26.6 Hz b) 1.5 m, 15 Hz c) 2 m, 20 Hz d) 1 m, 20 Hz

d)

Arrange the following substances in terms of increasing molar entropy at standard room temperature and pressure: Ca(s), Cl2(g), Cl2(l), CaCl2(s) a) Cl2(g), Cl2(l), Ca(s), CaCl2(s) b) Cl2(g), Cl2(l), CaCl2(s), Ca(s) c) CaCl2(s), Ca(s), Cl2(l), Cl2(g) d) Ca(s), CaCl2(s), Cl2(l), Cl2(g)

d)

As light passes from one medium into another, its angle of refraction will always be the same as the incident angle if a) the index of refraction of the first medium is 1 and the second medium is greater than 1 b) the index of refraction of the second medium is 1 and the first medium is greater than 1 c) the index of refraction of both media is greater than 1 d) the index of refraction of both media is the same

d)

Heterocyclic amines are a very important type of amino group. One use of them includes being the base of DNA. The most important property however is their basicity due to nitrogen. Pyridine is a much stronger base than pyrrole because: A. pyrrole will lose its aromatic character if nitrogen accepts an acid. B. pyridine has a pair of electrons in an sp2 orbital that is available for sharing. C. the extra pair of electrons on nitrogen in pyrrole is involved in the pi cloud and therefore less available for sharing. D. All of the above.

d)

How much greater is the beat frequency for a pair of tones at 12000 Hz and 12001 Hz versus a pair of tones at 4000 Hz and 4001 Hz? a) The beat frequency is 3 times greater. b) The beat frequency is 33% greater. c) The beat frequency is 2 times greater. d) The beat frequencies are the same for the two pairs of tones.

d)

If the following redox reaction is run in a galvanic cell, which species acts as the anode? Li+ + Ag → Ag+ + Li (E° = -3.84 V) a) Li+ b) Ag c) Ag+ d) Li

d)

In an experiment, a radioactive metal atom experiences alpha decay and the alpha particles are collected as a gas. If the gas volume collected contains 2 x 10-6 moles, how many total atoms decayed? a) 12 x 1018 atoms b) 6 x 1020 atoms c) 1.2 x 1019 atoms d) 1.2 x 1018 atoms

d)

In the combustion of methane, what is the change in oxidation state of the carbon atom from the left side of the reaction to the right and what is the reducing agent? The reaction is as follows: CH4 + 2O2 → CO2 + 2H2O a) +4 and CH4 is the reducing agent. b) +8 and O2 is the reducing agent. c) +4 and O2 is the reducing agent. d) +8 and CH4 is the reducing agent.

d)

In which of the following types of radioactive decay is there a change in the mass number of the isotope? a) electron capture b) β+ emission c) gamma emission d) alpha decay

d)

Longitudinal waves through matter elicit distinctive, detailed sensory information to which human sense? a) Sight b) Taste c) Touch d) Hearing

d)

Nuclear imaging is a radiology modality which utilizes radioisotopes to produce images of internal organs. Patients are injected with a a radioisotope; this isotope is taken up by various organs with differential specificity. Radioactive decay occurs and the particles transmitted are recorded by a receiver. For a successful study, it is necessary for the particle to travel a long distance out of the body and to the receiver. Which of the following types of emission is likely recorded? a) alpha decay b) beta decay c) positron emission d) gamma emission

d)

Of the following choices, which is NOT most likely to cause diffraction to occur when light passes through the setup? a) Wide slit b) Narrow slit c) Pinhole d) Glass

d)

Radioactive decay involving gamma emission requires which of the following? a) Emission of a neutron. b) Emission of a proton. c) Emission of a positron. d) Gamma emission does not require any loss of particles from the nucleus.

d)

Simple mercury barometers were historically particularly useful because the high density of mercury allows a barometer to be only approximately 1 m tall to measure normal fluctuations in atmospheric pressure, which determined the height of the mercury. If a barometer reads a height of 1000 mmHg, what height would be read on a barometer using water instead? The density of mercury is 13.5 g/mL and that of water is 1 g/mL. a) 74 mm b) 74 cm c) 135 cm d) 13.5 m

d)

The ion NH4+ can be described as a: I. Bronsted-Lowry Acid II. Arrhenius Acid III. Lewis Acid a) II only b) I and II only c) III only d) I, II, and III

d)

The mirror image of a carbon with sp2 hybridization is its a) enantiomer b) tautomer c) diastereomer d) none of the above

d)

Three capacitors with capacitance of 2 F, 4 F, and 8 F can be arranged in any way within a circuit. What is the maximum capacitance achievable by the three capacitors? a) 7/8 F b) 8 F c) 8.75 F d) 14 F

d)

Two biochemical mechanisms use the same reactants to produce the same products. The simplified, balanced reaction for both mechanisms is 2A + B → 2C. If one biochemical mechanism performs the reaction in 2 steps but the other mechanism performs it in 4 steps, how does the net enthalpy change of the reaction differ between the two biochemical mechanisms? a) The enthalpy change for 4 steps is double the enthalpy change for 2 steps b) The enthalpy change for 4 steps is 4 times more than the enthalpy change for 2 steps c) The enthalpy change for 4 steps is half the enthalpy change for 2 steps d) The enthalpy change for 4 steps is the same as the enthalpy change for 2 steps

d)

When an observer doubles their distance from a point source of light, the amount of energy received: a) increases by a factor of 2 b) increases by a factor of 4 c) decreases by a factor of 2 d) decreases by a factor of 4

d)

Which is a feature of gamma rays? a) They have the longest wavelength in the electromagnetic spectrum b) They have the least energy in the electromagnetic spectrum c) They are emitted by electrons from outside the nucleus d) They can kill cells

d)

Which of the following are examples of colligative properties? I. freezing point depression II. osmotic pressure III. boiling point elevation a) III only b) I and III only c) I only d) I, II and III

d)

Which of the following can be used as a half-cell in an electrochemical cell along with Cu/Cu2+? I. Al3+ + 3e- → Al (E0 = -0.76) II. Cu2+ + 2e- → Cu (E0 = 0.34) III. F2 + 2e- → 2F- (E0 = 2.87) a) I and III only b) II only c) III only d) I, II and III

d)

Which of the following compounds containing solely nitrogen and oxygen have an approximate percent composition of oxygen of 65%? a) NO b) NO2 c) N2O2 d) N2O3

d)

Which of the following is a spontaneous process? a) A process where the change in entropy of the system is positive. b) Two gases in one container maintaining different temperatures. c) The precipitation of sodium chloride when 1 mole of NaCl is added 2L of water. d) None of the above.

d)

Which of the following is not a feature of all waves? a) They transport energy through space b) They have an amplitude c) They have a frequency d) They transport mass through space

d)

Which of the following is the closest approximation to the value of Avogadro's constant? a) 6.48 x 1013 b) 6.67 x 10-11 c) 6.63 x 10-34 d) 6.02 x 1023

d)

Which of the following is true for a dielectric material? a) When placed in an electric field, electric charge begins to flow through the material. b) They serve the same purpose as conductors within a circuit. c) They are important components of voltmeters in circuits. d) They may be used in the manufacture of capacitors.

d)

Which of the following occurs with light but not with sound? a) Doppler effect b) Diffraction c) Refraction d) Travel through vacuum

d)

Which of the following solutions would have the highest boiling point? a) 1 M LiCl b) 1 M NaCl c) 1 M KCl d) All of the above solutions will have the same boiling point.

d)

Which of the properties are not examples of colligative properties for solutions? a) osmotic pressure b) freezing point depression c) boiling point elevation d) reactivity of the solution

d)

the focal length of a mirror is 2 meters. What is its radius of curvature? a) .25 m b) .5 m c) 2 m d) 4 m

d)

Jimmy and Nate both volunteer at the dog pound. Jimmy loves animals of all kinds and loves the chance to be around dogs. Nate doesn't particularly like animals, but he needs service hours for a club he is in at school. Jimmy recently watched a television program about Korea. The show ran a segment on a restaurant that served dog meat as a main dish. When jimmy saw this part of the program, he was horrified. Which of the following best describes Jimmy's viewpoint and subsequent reaction? a) None of these b) Discrimination c) Stereotype d) Ethnocentric

d) "ethnocentrism" can be described as the act of judging another culture by one's own standards. Jimmy's horror associated with viewing Koreans eating dogs in the program is based on his own experiences and his inability to view the world through the eyes of those individuals in the program. If this situation descried a stereotype, then it would have detailed over-generalized notions or ideas about a group, position or other thing. Discrimination is treating someone differently than others because of a characteristic, such as religion or race, and not necessarily merits

Biuret reagent is a solution which reacts with proteins to reduce Cu2+ to Cu+ which allows for quantitative detection at 540 nm. The best method for quantifying the protein would be: a) Infrared Spectroscopy b) H1 NMR c) Mass Spectrometry d) UV-Visible Spectroscopy

d) 540 nm falls within the range of visible light, and UV-Visible spectroscopy is intended to be used for quantitative detection (rather than qualitative identification like Mass Spec, IR, or NMR). This makes (D) the correct answer.

How many signals for 13C-NMR would we expect for bromobenzene? a) 1 signal b) 2 signals c) 3 signals d) 4 signals

d) A 13C-NMR on bromobenzene would show 4 distinct signals (from 4 groups of distinct, equivalent carbon groups). Carbon 1 (with the bromide) produces its own signal. Carbon 2 and 6 are equivalent and create their own signal. Carbon 3 and 5 are also equivalent and create their own signal. The final signal is created by carbon 4.

When metallic substances lose electrons, they are trying to achieve the electron configuration of what? A. The metal immediately before it on the periodic table. B. The metal immediately after it on the periodic table. C. The nearest halogen. D. The previous noble gas.

d) A metal prefers to lose electrons so that it has the configuration of 8 around its valence shell so that it is equivalent to the stable noble gas previous to it.

Which process is expected to begin earliest in a prolonged fast? a) Ketone bodies are used by the brain. b) Glycogen storage is halted. c) Proteins are broken down. d) Enzyme phosphorylation and dephosphorylation.

d) A prolonged fast is characterized by an increase in glucagon, which accomplishes its cellular activity by phosphorylating and dephosphorylating metabolic enzymes. Glycogen storage, choice (B), is then halted, but this requires enzyme regulation by glucagon to occur. Later in the postabsorptive state, protein breakdown, choice (C), begins. Eventually, in starvation, ketone bodies, choice (A), are used by the brain for its main energy source.

A group of researchers would like to separate DNA fragments based on their respective sizes. These researchers should employ a(n): a) distillation. b) ion-exchange chromatography. c) western blot. d) southern blot.

d) A southern blot is a technique in which DNA fragments can be separated based on size after an electric field is applied. Thus (D) is the correct answer.

What stage of protein synthesis does NOT require energy? a) Initiation b) Elongation c) Termination d) All stages of protein synthesis require energy.

d) All three stages of protein synthesis (initiation, elongation, and termination) require large amounts of energy.

Luteinizing hormone generally surges and peaks in women immediately prior to which of the following? a) menstruation b) fertilization c) birth d) ovulation

d) Although they fluctuate throughout the menstrual cycle, both FSH and LH peak shortly before ovulation each cycle and help stimulate release of the egg.

In a particular synapse, an acetylcholinesterase inhibitor is administered. Which of the following impacts will be seen on the neuronal network? a) Decreased production of acetylcholine b) Decrease in neuronal stimulation c) Increased rate of fatigue in the pre-synaptic neuron d) Continuous stimulation of the post-synaptic neuron

d) An acetylcholinesterase inhibitor will inhibit the action of acetylcholinesterase. Acetylcholinesterase, as the name implies, is an enzyme that breaks down acetylcholine, the neurotransmitter that results in the stimulation of the post-synaptic neuron; this is one of the enzymes you should be familiar with for the MCAT. If such an inhibitor was administered, then the neurotransmitter would never be degraded and there would be a prolonged, continuous stimulation of the post-synaptic neuron. Thus (D) is correct.

Which of the following accurately describes anaerobic respiration? a) It requires H2O as a terminal electron acceptor b) It cannot function in the presence oxygen c) It is only found among chemotrophs d) It can function without oxygen

d) Anaerobic respiration can function in the presence of oxygen, but does not require oxygen in its chemical pathways. Organisms which cannot function in the presence of oxygen are called obligate anaerobes, but their susceptibility to oxygen is due to reasons other than their mechanisms for respiration.

The stage of mitosis during which the chromosomes are most condensed is called: a) interphase. b) prophase. c) metaphase. d) anaphase.

d) Anaphase is the stage where the twin chromosomes split apart from each other and migrate to opposite poles of the cell. To assist with segregation of the chromosomes, the chromosomes are most condensed during this stage. Thus (D) is the correct answer.

An experimenter is working with an electrochemical cell, although he is unsure whether it is voltaic or electrolytic. There is a salt bridge for the cell composed of potassium iodide. What can the experimenter conclude? a) K+ will travel to the anode if the cell is electrolytic b) K+ will travel to the anode if the cell is voltaic c) I- will travel to the anode if the cell is electrolytic d) I- will travel to the cathode if the cell is voltaic

c)

A deficiency in the body of chief cells may result in: a) decreased protein digestion. b) increased calcium reabsorption. c) decreased sodium excretion. d) decreased bile production.

a) Gastric chief cells are responsible for the release of pepsinogen which is a zymogen to pepsin which is important for protein digestion. Thus (A) is the correct answer.

What is the hybridization of a carbonyl carbon in a carboxylic acid? a) sp b) sp2 c) sp3 d) sp3d

b)

Equal moles of the 4 different gases are placed in a closed container with a small pinhole opening in its side, they are: propane, methane, ethane, and chloromethane. After a short period has passed, which gas would have the lowest mole fraction? a) Propane b) Methane c) Ethane d) Chloromethane

b)

Gas A diffuses effuses through a hole at a rate R. If gas B is quadruple the mass of gas A, how fast will gas B diffuse through the hole? a) R/4 b) R/2 c) R/sqrt(2) d) R

b)

Gas A has a molar mass four times the mass of gas B. The rate of diffusion of gas A will be: a) one-quarter that of gas B. b) half that of gas B. c) the same as that of gas B. d) double that of gas B.

b)

In the reaction between BH3 and N(CH3)3 to form BH3N(CH3)3, the N(CH3)3 acts as which of the following? a)Lewis acid b) Lewis base c) Bronsted-Lowry acid d) Bronsted-Lowry base

b)

The buoyant force on a sunken ship block of iron is equal to: a) the weight of the iron block b) the weight of the water displaced by the iron block c) the weight of the pressure difference between the surface of the water and the center of mass of the block d) the weight of the water below the iron block

b)

The hybridization of the carbon in ethyne is: a) s. b) sp. c) sp2. d) sp3.

b)

The linear relationship of gas volume and temperature at constant pressure is independent of which of the following? a) Amount of gas, but not the type of gas b) Type of gas, but not the amount of gas c) Both amount and type of gas d) Neither amount of gas, nor the type of gas

b)

The molecular weight of a gas is 4 times greater than that of another gas. What is the relative rate of diffusion between the two gases? (i.e. The heavier gas diffuses ____ times as fast as the lighter gas). a) 0.25 b) 0.5 c) 4 d) 8

b)

Two volatile liquids, A and B, are combined as a solution in a closed beaker. There are 3 moles of liquid A and 9 moles of liquid B. The vapor pressure of liquid A is 10 mmHg and the vapor pressure of liquid B is 20 mmHg. Which of the following depicts the vapor pressure of the solution? a) 16.7 mmHg b) 17.5 mmHg c) 19.5 mmHg d) 21.5 mmHg

b)

Under which conditions are gases most soluble in water? a) high pressure and high temperature b) high pressure and low temperature c) low pressure and high temperature d) low pressure and low temperature

b)

A car traveling at 100 m/s must decelerate to standstill in 100m. What is the magnitude of the deceleration of the car? a) 25 m/s2 b) 50 m/s2 c) 66 m/s2 d) 100 m/s2

b) We can use the equation v2 = v02 + 2ad. Substitution yields -1002 = 2*a*100, thus a = -50 m/s2, thus (B) is the correct answer.

Triacylglycerol deposits can be observed in the cytosol as oil droplets. They serve as deposits of metabolic fuel that be be utilized when the cell needs additional energy to divide or when other fuel supplies are low. In animals, adipocytes store large amounts of fat, being found primarily under the skin, around mammary glands, or in the abdominal cavity. What happens during saponification? A. Triacylglycerols undergo a condensation reaction B. Triacylglycerols undergo ester hydrolysis C. Fatty acid salts are produced using a strong acid D. Fatty acid salts are bound to albumin E. None of the above

b) Saponification is the ester hydrolysis of triacylglycerol with the help of a strong base, like sodium or potassium hydroxide to form glycerol and fatty acid salts. This is not a condensation reaction, eliminating A. C is incorrect since it is a strong base that produces fatty acid salts. Although fatty acids travel the body bound to albumin, this has nothing to do with saponification. This eliminates D. Ultimately, B is correct.

0.045 moles of NaOH are used to titrate 500 mL of a 0.030 M solution of an acid. What is the most likely identity of the acid? a) HCl b) H2SO4 c) H3PO4 d) Cannot be determined based on the given information.

c)

A buffer solution can be prepared with a weak acid combined with which of the following? a) a weak base b) water c) the weak acid's conjugate base d) a strong acid

c)

Which of the following is not involved with Hfr strains of bacteria? a) Sex pilus b) Conjugation c) nucleosome d) F plasmid

c) Without recalling what an Hfr strain is, you can simply perform a process of elimination on this question. F plasmids, and sex pili are both involved with conjugation. You can therefore deduce that the three are related. Nucleosomes are present in eukaryotes, so clearly they are not involved with bacteria

A student has crystallized a compound and is concerned there may be an impurity. The presence of the impurity can be most easily determined by which of the following techniques? a) fractional distillation b) rotary evaporation c) melting point analysis d) thin layer chromatography

c) Thin layer chromatography is often a good way to look for multiple compounds, but its major downfalls are a) it requires large concentrations of each and substance to be present and would not work for minor impurities and b) it requires that each compound has sufficiently different physical properties as to visibly separate. Rotary evaporation and fractional distillation will help to separate two compounds but in this case would not work well for solids nor would they be helpful in determining whether there is an impurity. Mixed-melting point analyses are often used to determine purity of samples due to freezing point depression; presence of an impurity lowers the melting point and can therefore be easily determined.

Lipids are the major component of the phospholipid bilayer, which is undoubtedly the most important structural component of the cell. Phospholipids unique ability to form a bilayer allows cells to function with discrete interiors that are separate from the external environment. Which of the following is true of amphipathic molecules? A. They form spheres in any environment, with hydrophobic elements interior and hydrophilic exterior B. They have one fatty acid chain and one polar head group C. They are vital to the formation of phospholipid bilayers and soap bubbles D. They have a glycerol base E. None of the above

c) Although amphipathic molecules take on spherical forms, the formation depends on the solvent. If the solvent was water, then the hydrophobic elements would be interior, but if it was an organic solvent, then the hydrophobic elements would be on the exterior. This eliminates A. B and D describe phospholipids and sphingolipids and triacylglycerols, respectively. Therefore, these are not universally true statements for amphipathic molecules, rather just statements for these particular molecules. Ultimately, C is the best answer choice.

In the ear, sound is conveyed through the transfer of vibrational energy into the production of action potentials within specialized neuronal cells called hair cells. These cells are surrounded in a fluid called endolymph. Endolymph, unlike other bodily fluids, contains extremely high concentrations of potassium ions (K+). During excitation from vibrations, potassium flows into hair cells. Which of the following holds true regarding this phenomenon? a) Hyperpolarization of the hair cells occurs, resulting in excitation of the cells b) Sodium acts as the depolarizing agent for hair cells c) Membrane potential of the hair cells drops upon stimulation d) Hair cells become depolarized from the influx of potassium

d) This question is a bit tricky - normally, we are used to neurons having sodium flow into them, resulting in depolarization and excitation. Normally, potassium has a hyperpolarizing effect (i.e. it drops membrane potential). This case has everything reversed - potassium is the ion flowing into the cells, causing the depolarization. Membrane potential will increase when potassium flows into the cell (because potassium is a positively charged ion), thus (C) is false. (B) is false because sodium is not the depolarizing agent, potassium is. (A) is also false because cells will depolarize, NOT hyperpolarize. Thus, (D) is the correct answer.

The third harmonic of a standing wave between two walls has a wavelength of 1.5 m. What is the distance between the walls? a) 0.5 m b) 1.5 m c) 2.25 m d) 4.5 m

c)

A stone of mass m sits atop a hill of height h. As it rolls downhill, which of the following is true? 1. Half way down the hill, PE = 1/2 mgh 2. half way down the hill, PE = 1/4 mgh 3. half way down the hill, PE = mg(square root)h 4. half way down the hill, PE still equals mgh 5. none of these is true None of these is true. 5 3 4 2 1

1. initially, all the mechanical energy in the stone was potential energy and none was kinetic energy: ME = KE +PE. PE is "stored" in the stone-hill system by rolling the stone up hill. It is obvious that it takes half as much energy to roll the stone half way up the hill, compared with rolling it to the top. At the bottom of the hill, all of the PE will have been converted into KE, given by the formula KE = 1/2 mv^2 since the PE was 1/2 mgh when rolling the stone halvway up hill, it is the same as it rolls down hill

If the amount of acetylcholinesterase, an enzyme that breaks down acetylcholine, is increased, which of the following would likely be the result? a) Weakness of muscle movements b) Excessive pain or discomfort c) Mood swings and mood instability d) Auditory and visual hallucinations

A is the correct answer. If there were increased amounts of acetylcholinesterase, more acetylcholine would be degraded, lowering acetylcholine levels in the body. Low levels of acetylcholine would result in weakness or paralysis of muscles. Pain, choice (B), could result if one was injured and endorphins were found in low levels. Mood swings, choice (C), could be a result of varying levels of serotonin. Hallucinations, choice (D), have been seen to result from high levels of dopamine.

Which of the following anions is the strongest Bronsted base? A. CH3COO- B. NO3- C. HSO4- D. H2PO4-

A) Carboxylic acids are considered to be among the strongest organic acids but in comparison with all types of acids, carboxylic acids are very weak. By far, the protonated form of answer choice A (acetic acid is the IUPAC name; ethanoic acid is the systematic way to name it) would be the weakest of that group (after all, we are comparing it with nitric acid, sulfuric acid and phosphoric acid). Logically, a strong acid would create a weak conjugate base, otherwise the acid would not give up the proton readily. Thus the reverse is true: a weak acid has a strong conjugate base.

The many steps of glycolysis all exist in a state of dynamic equilibrium between reactant and product concentrations. Which of the following actions does NOT affect the equilibrium position of a reaction? a) Adding or subtracting heat b) Adding or removing a catalyst c) Increasing or decreasing concentrations of reactants d) Increasing or decreasing volumes of reactants

B is the correct answer. The equilibrium of a reaction can be changed by several factors. Adding or subtracting heat, choice (A), would shift the equilibrium based on the enthalpy change of the reaction. Increasing reactant concentrations would shift the equilibrium in the direction of the product, and the opposite would occur if reactant concentrations were decreased, eliminating choice (C). Changing the volume of a reactant would affect any reaction with gaseous reactants or products, eliminating choice (D). While adding or removing a catalyst would change the reaction rate, it would not change where the equilibrium lies.

Infrared spectroscopy is often used to determine the presence of a carbonyl group in a compound. It is a strong band appearing at about 1700 cm^-1 in aldehydes, ketones, and carboxylic acids and their derivatives. A carboxylic acid will show another carbon oxygen stretching band at: A. A higher frequency. B. A lower frequency. C. The same frequency. D. A frequency in the ultraviolet region of the electromagnetic spectrum.

B) A C-O single bond is weaker than a double bond. Therefore, less energy is needed to induce the stretching vibration. Remember reciprocal centimeters is a measure of frequency and energy is directly proportional to the frequency.

The carbonyl group is actually one of the most common functional groups in organic chemistry. It is a component of many different functional groups, including carboxylic acids, esters, amides, anhydrides, and several other compounds. Which of the following is not true of carbonyls? A. The carbonyl carbon is electrophilic B. The carbonyl oxygen is electron withdrawing C. A resonance structure places the positive charge on the carbonyl carbon D. The pie electrons are mobile and subsequently pulled toward the carbonyl carbon E. None of the above

D) Carbonyls possess a difference in reactivity between the carbon and oxygen atoms. The more electronegative oxygen draws in the bonding electrons, making it electron withdrawing. This makes the carbonyl carbon electrophilic, ruling out both A and B. One resonance structure does push the pie electrons onto the oxygen and subsequently create a positively charged carbonyl carbon. This eliminates C. As discussed, the pie electrons move toward the oxygen, not the carbonyl carbon, making D the correct answer.

What happens to the kinetic energy of a race car if its speed is tripled? A. The kinetic energy increases 3 times its original value. B. The kinetic energy increases 4.5 times its original value. C. The kinetic energy increases 6 times its original value. D. The kinetic energy increases 9 times its original value.

D) Kinetic energy is: KE = (1/2)mv2. The kinetic energy is directly proportional to the square of the velocity (or speed). If the speed is multiplied by 3 (tripled), the KE must be multiplied by 32 = 9. Sidenote, race car spelled backwards is still race car.

DNA replication cannot extend all the way to the end of a chromosome. The result of this is loss of sequences and therefore information with each round of replication. Our cells cleverly devise a solution: a simple repeating unit (TTAGGG) at the end of the DNA. This is called a telomere. Some of this sequence, which is lost in each round of replication, is replaced by telomerase. What type of cells would you expect telomerase to be more active in? A. Cancer cells B. Rapidly dividing cells C. Hepatocytes D. Neurons E. A and B

E) The question stem points you toward cells that are dividing more. These cells will be losing regions of their telomeres and subsequently have higher levels of telomerase activity. Cancer cells, which are characterized by unrestrained growth certainly fit this bill. Rapidly dividing cells and cancer cells are kind of one in the same, so B fits the bill as well. Unless there is chronic inflammation, such as in the presence of Hepatitis B or C, hepatocytes (which are liver cells) will not be rapidly dividing. Neurons are not rapidly dividing either. Ultimately, E is the correct answer.

A barrel of water with radius of 2.0 m sits on top of an 8-meter-high wall. A hole of radius 1 cm forms about 5 m down from the level of the water in the barrel. What is the velocity of the water as it leaves the hole? Use a water flow approach. Remember that Bernoulli's equation is: p1 + pgy1 + (1/2)pv12 = p2 +pgy2 + (1/2)pv22 A. 4 m/s B. 10 m/s C. 12 m/s D. 20 m/s

First apply the flow equation: A1v1 = A2v2, where A2 and v2 are the cross section and velocity of the top surface of the water: A1v1 = A2v2 v1*pi* (1 * 10-2 m)2 = v2*pi*(2m2) v1 = 4m2/ (1 * 10-4 m2) * v2 Solving for v1 gives us v1 = (4 * 104 m2/s) v2 Though this does not give us an exact answer yet, it DOES give us important info! That is the velocity of the top surface of the water (v2) is insignificant compared to the velocity of the water coming out of the hole (v1). This allows us to set v2 = 0 in our second equation, Bernoulli's equation: p1 + pgy1 + (1/2)pv12 = p2 +pgy2 + (1/2)pv22 Not only can we set v2 = 0, but we can also recognize that in a 5 meter-high column of water, the pressure at the bottom (p2) and bottom (p1) will be essentially the same, due to the fact that the additional pressure added by 5 meters of water is insignificant compared with the atmospheric pressure at the top (p1). Thus, the pressure terms can also be neglected, and the Bernoulli equation simplifies to give us: pgy1 + (1/2)pv12 = pgy2 v12 = 2g(y2 - y1) Solving for v1 gives: v1 = Sqrt(2(10m/s2)*5m)) = 10 m/s, or answer B.

C6H12O6+O2→CO2+H2O Which of the following is true, assuming the reaction goes to completion? I. There is an increase in ΔS, entropy II. ΔH<0 III. At equilibrium, ΔG=0 IV. Oxygen is the reducing agent

I, II, and III this question ties together the reaction for oxidation of glucose with several thermodynamic principles the first option, stating that there is an increase of entropy, is true. when balanced, we see that there is an increase in total number of molecules when the reaction completes; thus, there will be an increase in entropy. the second option states that enthalpy, or deltaH, is less than zero. This is also true, as it implies that this is an exothermic (or heat generating) reaction. The oxidation of glucose is how our bodies generate heat and keep homeostatsis the third option, stating that gibb's free energy is zero at equilibrium is also true. Any equation will have deltaG = 0 at equilibrium the last option, stating that oxygen is the reducing agent is false. oxygen is actually the oxidizing agent and is itself reduced

A metal rod that you use for LARP purposes is 2 meters long. Its coefficient of linear expansion is 10-6 K-1. After heating it to 1080 degrees Celsius for remolding, you let it cool to 80 degrees Celsius. What is the final length of the rod? A. 1.992 m B. 1.994 m C. 1.996 m D. 1.998 m E. 2.000 m

The thermal expansion formula is: ΔL=αLΔT ΔL=(10-6 K-1)(2 m)(80 K - 1080 K) - note the size unit is the same for Kelvin and Celsius, so there is no need to convert here ΔL= -0.002 m L= 1.998m

Which of the following cell types in the central nervous system are responsible for cerebrospinal fluid (CSF) production? a) ependymal cells b) schwann cells c) astrocytes d) oligodendrocytes

a) Ependymal cells are responsible for CSF formation, thus (A) is the correct answer. Schwann cells generally myelinate nerves in the periphery, astrocytes are responsible for formation of the blood-brain barrier, and oligodendrocytes produce myelin in the central nervous system.

242/95Am undergoes β- radioactive decay, converting it into a) 242/95Am- b) 241/95Am c) 242/96Cm d) 242/94Pu

c)

A capacitor is placed in a circuit containing a 9 V battery. The capacitor is composed of two circular metal sheets of radius R separated by a distance D. If R is doubled and D is halved, what is the effect on capacitance? a) Increases 8 times b) Increases 4 times c) Increases 2 times d) remains constant

a)

A gas container with a movable piston inside currently shows that the piston is resting at the halfway mark in the container. If this piston were moved from the halfway mark all the way to the very top of the container, by what factor would the pressure change? a) Decrease by a factor of 2 b) Remains the same c) Increase by a factor of 2 d) Increase by a factor of 4

a)

A mirror with a focal length of -2.5 m. An object is placed 7.5 m in front of the mirror. Where will the image of the object show up? a) 1.9 m behind the mirror b)1.9 m in front of the mirror c)0.33 m behind the mirror d) 0.33 m in front of the mirror

a)

Chromatin found in a lightly-packed form that is readily available for transcription is referred to as: a) euchromatin. b) heterochromatin. c) synchromatin. d) prochromatin.

a) Euchromatin refers to lightly-packed chromatin, whereas heterochromatin is condensed and not readily available for transcription. Thus (A) is the correct answer.

A researcher is examining an energy source and is determining the type of wave emitted. She observes that the wave is unable to propagate in a vacuum. If the wave is placed in front of a barrier with a single thin slit, the wave diffracts out of the slit. Upon observing movement, she finds the particles do not oscillate in the direction of the motion of the wave. Based on these observations, she can most safely conclude the wave is a a) transverse wave b) longitudinal wave c) both transverse and longitudinal d) neither transverse nor longitudinal

a)

A study is conducted on childhood obesity to understand the link between obesity and the consumption of high fructose corn syrup, a common sweetener. In the study, the intake of high fructose corn syrup is the: a) independent variable. b) dependent variable. c) control. d) hypothesis.

a)

An unknown liquid has been isolated in a laboratory. Scientists added 100 J of heat energy with a constant source of heat. The temperature of the liquid did not increase. Which of the following could explain the reason the temperature did not increase? a) The liquid is at its boiling point b) The liquid is at its freezing point c) The liquid has a very low heat capacity d) The molecular bonds of the liquid do not respond to heat energy

a)

Fluorescence is produced when a molecule enters an excited state and releases a photon of a particular wavelength. Which of the following colors of fluorescence would be indicative of the lowest energy? a) Red b) Blue c) Violet d) Green

a)

Heat transfer through the movement of bulk amounts of molecules is referred to as: a) convection. b) conduction. c) transduction. d) radiation.

a)

In radioactive decay alpha radiation can be shielded with a piece of paper, requiring far less shielding than gamma or beta radiation. This is primarily due to which of the following? a) Alpha particles are far more massive than other forms of radiation b) Alpha particles are not as harmful as other forms of radiation c) Alpha particles are uncharged and thus do not have high penetration abilities d) Alpha particles are emitted at a far higher energy than other forms of radiation

a)

Lead chloride dissolves in aqueous solution in the following fashion: PbCl2(s) → Pb2+(aq) + 2Cl-(aq). An experiment is performed by adding 100 g of solid lead chloride to 500 mL of water; 85 g of lead chloride are found to be undissolved at the end of the experiment. Which of the following is the solubility product for the reaction? Assume the molar weight of lead chloride is 300 g. a) 0.004 b) 0.04 c) 0.24 d) 0.001

a)

One method for measuring the concentration of an analyte is to pass light through the sample and to measure how much is lost. This is known as percent transmission. Another method is pass light through the sample and to measure light at a longer wavelength (lower energy) than the incident light (the light shone onto the sample). What property of the analyte is being measured when a longer wavelength is measured (as opposed to percent transmission)? a) fluorescence b) absorbance c) color d) density

a)

The following reaction has a negative change in enthalpy: 2NO(g)+O2(g) <-->2NO2(g). Which of the following would increase the ratio of NO2 to NO at equilibrium? a) Decreasing the volume of the system. b) Inserting a catalyst. c) Removing oxygen from the system. d) Increasing the temperature.

a)

The pKa of the amino acid tyrosine is between 10.0 and 10.3. Tyrosine molecule R groups are phenolics, with the hydroxyl hydrogen titrating in the pH range given. If a given solution of tyrosine molecules is brought from pH 9 to pH 11, what do you expect to occur to the hydroxyl group? a) The hydroxyl will go from being protonated at pH 9 to being deprotonated at pH 11 b) The hydroxyl will go from being deprotonated at pH 9 to being protonated at pH 11 c) The hydroxyl will remain deprotonated during the pH shift d) The hydroxyl will remain protonated during the pH shift

a)

The reflected image in a convex mirror will be a)virtual and upright b) virtual and inverted c) real and upright d) real and inverted

a)

The vapor pressure of an unknown pure liquid is 28 mmHg. If 4 moles of nonvolatile solute are dissolved into the liquid to form 7 moles of solution, what is the vapor pressure of the solution? a) 12 mmHg b) 16 mmHg c) 49 mmHg d) There is not enough information to determine the answer.

a)

What beat frequency would be heard between two tones played simultaneously at 20 Hz and 25 Hz? a) 5 Hz b) 45 Hz c) 0.20 Hz d) 0.25 Hz

a)

When you first meet Dustin, he is very rude to you. You run into him twice more and he is very friendly, but you still dislike him because of your first meeting. What impression bias does this describe? a) Primacy effect b) Recency effect c) Reliance on central traits d) Proximity

a)

Which of the following is not a colligative property? a) Increased vapor pressure with the addition of a nonvolatile solute to a solution. b) Increase boiling temperature with the addition of a nonvolatile solute to a solution. c) Decreased freezing temperature with the addition of solute to a solution. d) Increased osmotic pressure with the addition of solute to a solution.

a)

Which of the following statements regarding waves is FALSE? a) Light experiences diffraction but sound does not. b) Light slows down as it moves from air to water but sound speeds up. c) Light is a transverse wave while sound is a longitudinal wave. d) Both light and sound have a period, frequency, and a wavelength.

a)

Which of the following statements regarding waves is FALSE? a) Light experiences diffraction but sound does not. b) Light slows down as it moves from air to water but sound speeds up. c) Light is a transverse wave while sound is a longitudinal wave. d)Both light and sound have a period, frequency, and a wavelength.

a)

Infrared spectroscopy relies in the absorption of light by bonds in which there is a permanent dipole. Which of the following molecules would have the weakest absorbance of infrared light? a) Cl-Cl b) C=O c) C-H d) O-H

a) Dipoles are present to some degree in all of the bonds listed except for Cl-Cl. This is because the electronegativities of the two atoms in the bonds are different, which creates a dipole (some stronger than others). Diatomic molecules have each atom with identical electronegativity, hence there is no dipole formed. Therefore, the bond will be unable to absorb infrared light.

Some cellular membranes sequester hydrogen ions on one side in order to create an acidic or basic environment. For example, the membrane of lysosomes contains proton pumps that move hydrogen ions into the lysosome. For a cell with the following half-reactions: How would decreasing the pH of the solution inside the cell affect the electromotive force (emf)? a) The emf would decrease. b) The emf would remain the same. c) The emf would increase. d) The emf would become zero.

a) A change in pH has a direct correlation to the hydrogen ion (H) concentration. Decreasing the pH increases the H+ concentration, which means the concentration of products has increased in the oxidation of sulfur dioxide. This means it would be harder to liberate electrons, thus decreasing the emf. One could also view this decrease in oxidation potential as an increase in reduction potential. If E°red,anode increases, then E°cell must decrease according to E°cell = Ered,cathode - E°red,anode

A student accidentally places her hand on a tack and quickly pulls her hand away. The tack represents a) a stimulus b) an impulse c) a response d) an effector

a) A stimulus is anything that causes a response. The tack was detected by a receptor in the students hand, impulses were sent from sensory neurons to interneurons in the students spinal cord, to motor neurons, which caused effectors in the students hand to contract the muscles, causing the movement. This is called a reflex. The impulse is the electrochemical charge that travels along the neurons, the response is the effect, or moving the hand, and the effector is the muscle or gland that causes the response.

In the formation of hemiacetals and hemiketals, alcohol is the nucleophile and the carbonyl carbon is the electrophile. However, in the formation of acetals and ketals, alcohol is still the nucleophile but the carbocation, previously the carbonyl carbon, is the electrophile. In a reaction between ammonia and glutaraldehyde, what will the major product be? A. An immine B. A cyanohydrin C. An aldehyde with a substituted ring D. An alcohol E. None of the above

a) All you need to know is that ammonia reacts with aldehydes to form immines. This is formally a condensation reaction and a substitution reaction, with the C=O of the carbonyl replacing the C=N double bond. This makes A correct. A cyanohydrin has a cyano and hydroxy attached to the same carbon, eliminating B. There is nothing hinting at a substituted ring, ruling out C. An alcohol is only formed when water reactions with aldehydes or ketones, ultimately forming geminal diols.

Which of the following characteristics is NOT attributed to antibodies? a) Antibodies bind to more than one distinct antigen. b) Antibodies label antigens for targeting by other immune cells. c) Antibodies can cause agglutination by interaction with antigen. d) Antibodies have two heavy chains and two light chains.

a) Antibodies are specific to a single antigen. Each B-cell produces a single type of antibody with a constant region that is specific to the host and a variable region that is specific to an antigen.

A membrane permeable only to water is placed between solutions A and B. Solution A contains 3 mM glucose and solution B contains 3 mM NaCl. In which direction will the water flow? a) from A to B b) from B to A c) neither; there are 3 mM of solute in both solutions d) neither; there is no force to drive the water in either direction

a) Because NaCl dissociates in water, each component of its dissolution counts as another solute. Since 3mM of NaCl is in the solution, that means there are 3mM of Na and 3mM of Cl, for a total of 6mM. Since the solute concentration is higher in solution B than in solution A, water will travel from solution A to solution B.

During fractional distillation, hydrocarbons are separated according to their a) boiling points b) melting points c) triple points d) saturation points

a) Because hydrocarbons differ in boiling points, fractional distillation separates the parts (fractions) of the mixture by heating the hydrocarbons in long columns until they form gases (vaporization). At various points in the tower the fractions (hydrocarbons) condense and are removed. This is possible because the hydrocarbons have different boiling points.

A stroke patient comprehends speech but cannot move her mouth to form words. Which of the following brain areas is likely affected? a) Broca's area b) Wernicke's Area c) Arcuate fasciculus d) Superior temporal gyrus

a) Broca's area governs the motor function of language. A stroke that affects Broca's area will leave receptive language intact, but word formation will be affected. A stroke affecting Wernicke's area, choice (B), will make it so the individual is unable to comprehend speech. A stroke affecting the arcuate fasciculus, choice (C), will result in an inability to repeat words heard but spontaneous language production is intact. The superior temporal gyrus, choice (D), is where Wernicke's area is located.

Certain functional groups will absorb at multiple different wavelengths in infrared spectroscopy. This absorbance at multiple wavelengths is due to a) different types of bond motions including vibrations and stretches. b) intramolecular interactions of other functional groups. c) resonant absorbance frequencies. d) conjugation in the molecule.

a) C) is a nonsense answer that does not apply to infrared spectroscopy in a relevant context. Conjugation affects wavelength of absorption, but this would not create multiple wavelengths of absorption, making (D) incorrect. (B) is incorrect because other functional groups will simply have their own absorption wavelengths. (A) is the correct answer because various functional groups have multiple degrees of freedom for their motion (wag, stretch, bend, rock, etc.) each of which can be excited at a particular wavelength. Therefore (A) is the correct answer.

Which of the following techniques is used to separate cellular proteins and is characterized by proteins leaving the mobile phase and associating with a negatively charged immobile substrate? a) Cation exchange chromatography b) Anion exchange chromatography c) Affinity chromatography d) Micellar liquid chromatography

a) Cation exchange chromatography involves separating substances based on their charges using an ion-exchange bead or resin containing negatively charged groups. For anion exchange chromatography, the bead or resin would instead contain positively charged groups. Affinity chromatography is used for highly specific interactions such as those between antigen and antibody or between enzyme and substrate. Lastly, micellar liquid chromatography achieves a separation of components based on polarity.

The stage of cell division that occurs without increase in cell size after division is called a) Cleavage b) Blastulation c) Gastrulation d) Fertilization

a) Cleaveage is the initial division of the cell after fertilization. It is the stage which leads directly to blastulation. Blastulation is then followed by gastrulation. Fertilization occurs before cleavage.

The swimming times for all members of a swim team are tracked over a six-month period in team-only practices and at public meets. For 14 of the 16 members, top times were clocked at the meets. What social phenomenon does this evidence support? a) Social facilitation b) Peer pressure c) Identification d) Group polarization

a) For 14 out of the 16 members, the record times were obtained during public meets. The fact that the team members performed better when in front of a crowd supports the notion of social facilitation.

A primary advantage of ganglia in vertebrates is their ability to a) process stimuli and responses faster than if the signal were to travel through the central nervous system. b) act as a backup to the central nervous system in cases where there is significant cerebral damage. c) detect stimuli that are finer than stimuli that are processed by the central nervous system. d) illicit a more complex response than the central nervous system.

a) Ganglia are collections of nerve cell bodies outside of the central nervous system. One major advantage to having ganglia in vertebrates (which have a central nervous system) is their ability to receive and process stimuli very quickly; the stimulus does not need to be sent to the central nervous system, processed, and sent back. Because ganglia are far less complex than the central nervous system, they cannot act as a backup, especially for cerebral function which is highly complex. This makes (B) incorrect. (C) is incorrect because stimuli are all still detected via neurons and there is no good reason for why ganglia are able to process finer stimuli than the central nervous system. (D) is incorrect because again, the ganglia are simpler than the central nervous system hence they cannot process more complex responses.

The advantage of coupling gas chromatography followed by mass spectrometry over simply mass spectrometry is that a) the GC-MS is capable of separating individual analytes prior to fragmentation in the MS b) the GC-MS is capable of fragmenting all the analytes at once prior to analysis on the GC c) the GC-MS requires less time to operate than the GC alone d) neither technique provides useful information on its own; only together can their data be put to any use

a) Gas chromatography separates analytes based on their physical properties, while mass spectrometry ionizes and fragments analytes for interpretation of their structure. Although their combined data are more useful than each of their data alone, it is incorrect to say that their data alone cannot be put to any use. Because the GC operates prior to the MS, so MS cannot fragment the analytes before GC separates them, making (B) incorrect. It is also incorrect to say that the coupled instrumentation takes less time to operate than a single one of them, since the time involved to run both instruments clearly requires the combined time of running each individually.

The anomers of D-(+)-glucose differ in their configuration around which of the following? A. C-1 B. C-5 C. C-6 D. C-2

a) Glucose anomers have a different orientation of the hydroxyl group on the C-1 carbon.

Chromosomes are composed of DNA wound around a group of small, basic proteins called histones. This is also referred to as chromatin. There are five histone proteins in eukaryotic cells. Which protein is not an element of the histone core? A. H1 B. H2A C. H2B D. H3 E. H4

a) H2A, H2B, H3, and H4 form the histone core. About 200 base pairs of DNA wrap around this core complex, forming a nucleosome. They appear like beads on a string under microscope. The protein not part of the core, H1, adds stability to the structure. The correct answer is therefore A.

Hypertension (high blood pressure) can be diagnosed by having two or more blood pressure readings higher than 140/90 on two different occasions, separated by a week. Suppose that the criteria were changed to include anyone with a reading higher than 130/80 on at least one occasion. How would this change the prevalence of diagnosed hypertension in the population? a) The prevalence would increase. b) The prevalence would decrease. c) The prevalence would remain the same. d) There is not enough information to determine the change in prevalence.

a) If the threshold for hypertension (high blood pressure) were lowered, more individuals would be fit the criteria for the disease. If the number of individuals with the disease increases and the population stays the same overall, there will be an increased prevalence of the disease.

There are potential risks associated with advancing biotechnology. For instance, safety concerns, like as increased resistance in viruses and bacteria can have negative effects on both us, as humans, and our environment. Ultimately, ethical questions arise, like is it ethical to test for potentially life-threatening genetic diseases and potentially terminate a pregnancy based on the results? Which of the following, differentiating DNA and RNA, is false? A. DNA replicates 5' to 3', while RNA is synthesized 3' to 5' B. The sugar in DNA is deoxyribose, while the sugar in RNA is ribose C. DNA uses the base thymine, while RNA uses uracil D. DNA is double stranded, while RNA is single-stranded E. None of the above

a) Let's go over the main differences between DNA and RNA first. DNA is double-stranded, with a deoxyribose sugar and the nitrogenous bases A, T, C, and G. On the other hand, RNA is generally single stranded, possesses a ribose sugar, and has the bases A, U, C, and G. A is the only false answer choice, since both DNA replication and RNA synthesis proceed in a 5' to 3' manner.

The primary function of lysosomes is to a) digest macromolecules, organelles, and microorganisms. b) be released and used as extracellular defense mechanisms. c) produce ATP for the cell. d) transport macromolecules to and from the nucleus.

a) Lysosomes are a common organelle used for digestive purposes. They contain powerful digestive enzymes and low pH to digest and recycle various cellular components. They are not released to the extracellular environment, are not used for energy production, and are not used as transport vesicles for the nucleus.

Matt and Cati discuss the reasons why they avoid driving above the speed limit. Matt says that he wants to avoid a traffic fine, while Cati says that speeding is dangerous and, if everyone did it, there would be more accidents and people would get hurt. According to Kohlberg, which of the following describes the phases of moral reasoning demonstrated by Matt and Cati, respectively? a) Preconventional; conventional b) Preconventional; postconventional c) Conventional; preconventional d) Postconventional; conventional

a) Matt's reasoning reflects a desire to avoid punishment, which reflects stage one in Kohlberg's preconventional phase (obedience). Cati's reasoning takes into account social order, reflecting stage four in the conventional phase (law and order).

If you treat 2-ethyl-1-hexanol with methylsulfonyl chloride in base, followed by reaction with pyridinium chlorochromate, and ultimately a final step in strong acid, what will the end product be? A. 2-ethyl-1-hexanol B. 2-ethylhexanal C. 2-ethylhexanoic acid D. 2-ethyl-1-hexane E. None of the above

a) Methylsulfonyl chloride is a protecting group for alcohols, converting them into mesylates. What would normally be an oxidation reaction (with regards to the alcohol) now does not occur. When the protecting agent is removed via the strong acid, we arrive at our starting product. Therefore, A is correct. B and C are the result of oxidation, which does not occur. Therefore, they are eliminated. D is a reduction product, which does not occur either.

A child is born with an extra chromosome in each of its cells. This condition is usually the result of a) nondisjunction b) problematic crossing over c) segregation d) hybridization

a) Nondisjunction is the result of the paired homologous chromosomes seperating unequally during meiosis. So instead of one of a particular chromosome going to each of the 4 resulting sex cells, one cell gets two chromosomes of that type. Then during fertilization that zygote gets three of that particular chromosome instead of the normal two, resulting in one extra chromosome. That zygote then undergoes mitosis, resulting in all of that organisms cells containing one extra chromosome.

Increased reabsorption of bone can result in osteoporosis, or significant decrease in the structural integrity of bone. Which of the following hormones, if released in high amounts, would result in osteoporosis? a) parathyroid hormone b) thyroid hormone c) calcitonin d) insulin

a) Parathyroid hormone results in bone resorption, thus an increased amount of parathyroid hormone release could result in osteoporosis. Thus (A) is the correct answer.

Ubiquinone is a biologically active quinone. It is also referred to as coenzyme Q. It is a vital electron carrier associated with complexes I through III of the electron transport chain. Which of the following relays the molecules correctly in terms of increasing acidity of their hydroxyl hydrogen? A. Cyclohexanol < hexanol < phenol B. Cyclohexanol < phenol < hexanol C. Phenol < hexanol < cyclohexanol D. Phenol < cyclohexanol < hexanol E. None of the above

a) Phenols have the most acidic hydroxyl hydrogens by far given the stabilization of the conjugate base by the conjugated ring system. This makes A the correct answer. For completeness though, the hydroxyl group of hexanol is slightly more acidic than that of cyclohexanol because the ring structure of cyclohexanol is slightly electron donating, ultimately making the hydroxyl hydrogen less acidic (destabilizing the conjugate base).

Which of the following amino acids is a common target of protein kinases? a) threonine b) arginine c) tryptophan d) glutamic acid

a) Protein kinases phosphorylate proteins at one of three amino acids: tyrosine, serine, and/or threonine. These are the only three amino acids with hydroxyl groups onto which phosphates can be attached.

Carbonyl has the unique ability to behave as either a nucleophile, as in condensation reactions, or an electrophile, as in nucleophilic addition reactions. If I wanted to create a geminal diol, what would I react? A. An aldehyde with water B. An aldehyde with an alcohol C. A ketone with an alcohol D. An aldehyde with two equivalents of alcohol E. A ketone with two equivalents of alcohol

a) Reacting an aldehyde with water would certainly create a geminal diol, which is also referred to as a 1,1-diol. Reacting aldehydes and ketones with alcohol gives hemiacetals and hemiketals, respectively. Doing the same with two equivalents of alcohol yields acetals and ketals, respectively. Ultimately, A is correct.

There are a myriad of different ways to study. Everyone eventually discovers what works best for them, however there is science that outlines the best way to encode information for later recall. Which of the below methods is most conducive to later recall? A. Semantic encoding B. Visual encoding C. Iconic encoding D. Acoustic encoding E. None of the above

a) Semantic encoding, or encoding information on the basis of its meaning, is the strongest method to encode information for later recall. This would make sense since it is not necessarily memorization if you simply understand it. Visual encoding is the weakest, with acoustic encoding being between the two. Iconic memory is actually a type of sensory memory, so it is not applicable here. Ultimately, A is correct.

An object undergoing simple harmonic motion is observed to have a time interval of 4 seconds between the two extremes of its displacement from equilibrium. What is the frequency of this motion? A. 0.125 cycles/second B. 0.25 cycles/second C. 1.25 cycles/second D. 4 cycles/second

a) Since it takes 4 seconds for the object to travel from one end of its displacement to the other (half a cycle), the time for a full cycle is 2(4 sec) = 8 sec. Thus frequency = 1/T = 1/8 = 0.125 Hz.

Using a given mass of H2O2, how would you calculate the mass of oxygen produced in the following reaction, assuming it goes to completion? A. (grams H2O2 consumed)(3 moles O2)(molar mass O2) / (molar mass H2O2)(2 moles H2O2) B. (grams H2O2 consumed)(molar mass O2) / (molar mass H2O2)(2 moles H2O2) C. (molar mass H2O2)(2 moles H2O2) / (grams H2O2 consumed)(molar mass O2) D. (grams H2O2 consumed)(3 moles O2) / (molar mass H2O2)(2 moles H2O2)(molar mass O2) E. None of the above

a) Since molar mass is measured in grams of a substance per moles of that particular substance, only A comes out with the appropriate unit: grams of oxygen. B has the units of grams per mole of oxygen, not grams of oxygen, eliminating it. C has the units of moles per gram of oxygen, eliminating it. Last, D has the units of mol2 per gram of oxygen, eliminating it as well.

Regarding neural communication, which statements are TRUE? I. The dendrites of a neuron receive messages from other neurons. II. The action potential starts when potassium ions enter the axon. III. Neural communication involves an electrochemical process. IV. The dendrites of the sending neuron secrete neurotransmitters into the synapse. a) I and III only b) I, II, and III only c) II and IV only d) I, II, III, and IV

a) Statements (I) and (III) are true. It is true that dendrites receive messages from other neurons. It is also true that neural communication is an electrochemical process. Answer (II) is incorrect because the action potential starts when sodium ions enter the axon. Answer (IV) is also incorrect because the synaptic vesicles, not the dendrites, of the sending neuron secrete neurotransmitters into the synapse. Thus, the correct answer is (A).

Imagine you are playing with a one year old child. They are able to play peek-a-boo with you. What stage of Piaget's cognitive development would you expect them to be in? A. Sensorimotor B. Preoperational C. Concrete operational D. Formal operational E. None of the above

a) The fact that they can play peek-a-boo means that they lack an understanding of object permanence, which is the idea that objects continue to exist even when out of view. The infant finds this game so entertaining because each time you reveal yourself, it is interpreted as if you have just come into existence, rather than continued to exist behind your hands. Object permanence is a milestone reached at the end of the sensorimotor period. This makes A the correct answer. Another way to evaluate this is given the age of the child, one year old. The sensorimotor period spans from birth until about two years of age.

Which of the following is the first line of defense for the immune system of the human body? a) epithelia b) digestive system c) blood d) lymphatic system

a) The first barrier that any pathogen will encounter when coming in contact with the human body is an epithelial layer. Hence this is the first line of defense for the human body against pathogens. In most cases, the epithelium in quesiton in the skin. Also, the digestive and respiratory epithelia guard against food and water-borne, and airborne pathogens.

Which of the following statements accurately describes the magnitude of the normal force (N) on a sled sliding down a frictionless roof that is inclined at x degrees with the horizontal? A. N decreases as x increases, but not proportionally. B. N is inversely proportional to x. C. N is proportional to x. d) N is constant, independent of x.

a) The normal force is the force that pushes up against on object. For an inclined plane, the formula for normal force is N = m*g*cos(x). The mass of the sled and gravity stay the same, so N must decrease as x increases due to the cosine function. Try 30 degrees for x and then 60 degrees for x in a calculator, you'll see that the normal force decreases, but does not decrease by a factor of 2.

A woman is at a restaurant and orders a spicy entreé. After the first bite, she experiences burning in her mouth and becomes concerned that her food is too hot for her. The next few bites are similarly uncomfortable, but after a while the spiciness seems to subside somewhat, and by the end of the meal, she doesn't notice the spice level. The end of the meal experience is best described as: a) adaptation. b) signal detection. c) a difference threshold. d) pain perception.

a) The spicy food can be considered an extreme stimulus because it eclipses what the woman believes she can handle in terms of heat. However, after experiencing the stimulus over and over, the experience of spice drops to barely perceptible. This is sensory adaptation: a reduction in response to a stimulus over time.

Which of the following types of spectroscopy is mainly used for determination of functional groups on organic molecules? a) IR b) NMR c) UV d) Atomic Emission

a) The various types of spectroscopy have different utilities for identifying various structures on molecules. IR (infrared) spectroscopy is able to identify structural groups, e.g., hydroxyl groups, carbon-carbon triple bonds, etc... Thus (A) is the correct answer.

A runner completes a lap on a circular track in three minutes. The track has a radius of 210ft. The runner ran at a constant speed around the track. Which of the following statements is true? a) The runner's average speed is greater than the runner's average velocity b) The runner's total distance traveled is equal to the runner's total displacement c) The runner never accelerated while running around the track d) The runner's average velocity is 7.3fts

a) This is a question that helps you see how displacement and velocity compare to distance and speed, respectively. Remember that the runner starts and stops at the same point on the track, so her total displacement is zero feet. since velocity = displacement/time, the runner's average velocity is 0ft/s Since the runner's average speed is greater than her average velocity, we can conclude this is the correct answer. Her average speed refers to her distance, rather than displacement, and is greater than zero speed = distancetime this is also important to remember! since the runner changed direction on the track, she accelerated and decelerated accordingly based on her position on the track. She did not have a constant acceleration

Which of the following is necessarily true for all viruses? a) Contains a protein coat which stores genetic information b) Genetic material from the virus enters the genome of the host c) Contains the enzyme reverse transcriptase d) Must be able to bind to at least some bacterial surface proteins

a) This problem can most easily be solved through process of elimination. (D) is incorrect because some viruses attack non-bacterial organisms. (C) is incorrect reverse transcriptase is only needed for RNA viruses who reverse transcribe their RNA into DNA, which then enters the genome of the host. (B) is incorrect because some viruses function in a way that the genetic material of the virus does not enter the genome of the host, but instead viral genetic information is simply translated in the cytosol and then degraded. That leaves (A) as the correct answer: it is true because all viruses contain some protein protection around its genetic information (whether DNA or RNA).

Twin studies allow psychology researchers to evaluate: I. effects of environment independent of genetic factors. II. effects of genetic factors independent of environment. III.social behaviors between individuals with similar upbringings. a) I only b) I and II c) II only d) I, II, and III

a) Twin studies allow researchers to compare individuals with identical genetic makeup. The constant is genetics and the dynamic variable is the environment, thus researchers can determine the effects of environment independent genetics. Thus (A) is the correct answer. III is not an element of twin studies.

A flagella is typically composed of: I. microtubules. II. microfilaments. III. intermediate filaments. a) I only b) I and II c) II and III d) I and III

a) Typically, flagella are mainly composed of microtubules in a 9+2 arrangement with various cross bridges for structure. Microfilaments and intermediate filaments are not thought of as very contributory to the structure of a flagella. Thus (A) is the correct answer.

In high doses, aspirin functions as a mitochondrial uncoupler. How would this affect glycogen stores? a) It causes depletion of glycogen stores. b) It has no effect on glycogen stores. c) It promotes additional storage of glucose as glycogen. d) Its effect on glycogen stores varies from cell to cell.

a) Uncouplers inhibit ATP synthesis without affecting the electron transport chain. Because the body must burn more fuel to maintain the proton-motive force, glycogen stores will be mobilized to feed into glycolysis, then the TCA, and finally oxidative phosphorylation.

Two patients who are identical twins are diagnosed with the same psychiatric illness. However, patient A exhibits less severe symptoms than patient B. This could be a direct result of which of the following? a) Patient A has more social support b) Patient B has more social support c) Patient B adheres to a proper treatment schedule more faithfully d) Genetic differences cause Patient A to exhibit less severe symptoms

a) Upon reading the question, the first important piece of information that is given is that the patients are identical twins. This rules out genetic differences as a direct cause of the difference in symptomology (D). Logically, we can rule out (C) because if patient B adhered to the treatment schedule more faithfully, and it was a proper treatment, then patient B should exhibit fewer symptoms (not patient A as in the question). This leaves options (A) and (B). Social support has been shown to attenuate the negative effects of stressors, which may account for much of the finding that social support attenuates mental health symptoms. Knowing this, (A) becomes the clear answer because patient A is exhibiting less symptom severity.

An azeotrope is a mixture of two or more liquids which distill together as if they were a single compound. Ethanol and water form an azeotrope, making it difficult to purify ethanol. Addition of benzene can help to solve this problem: benzene, ethanol, and water boil at a ratio of 7:17:76 water:ethanol:benzene. This leaves behind almost all of the excess ethanol. During a distillation, you work with a mixture whose ratio is 7:20:76. What remains after the water:ethanol:benzene azeotrope has boiled off? a) 3 parts ethanol b) Everything; the azeotrope will not boil if the liquids are not in the correct proportions. c) Nothing; the azeotrope will adjust to accommodate the extra 3 parts of ethanol d) This this cannot be determined based on the starting ratios because adjustments to the starting proportions can have unpredictable consequences on the ratio at which the azeotrope will boil.

a) We are given the ratio at which the azeotrope of water, ethanol, and benzene boils, and we are told that azeotropes evaporate at a fixed ratio. This tells us (D) is false because there is indeed predictability. Because the ratio is fixed (and thus does not change), we can eliminate (B) as well. (C) may be plausible, but remember that what matters is the final ratio being correct, not the starting ratio. In much the same way that a chemical reaction will proceed until the limiting reactant has been consumed, an azeotrope will evaporate until the limiting liquid is gone. In this case, ethanol is in excess, so it will remain alone.

How many hydrogen peaks (excluding bond-neighbor effects) would the molecule 3-ethyl-2-methylpentane show in its H-NMR? a) 5 b) 6 c) 8 d) 18

a) We can start with the hydrogens on the 1-carbon. We see that these hydrogens are all equivalent, are equivalent to the hydrogens on the 2-methyl group, thus this constitutes one peak. Then another peak from the hydrogen on the 2-carbon. Then an additional one from the 3-carbon. Then we see equivalent hydrogens on the 4-carbon and the 1-carbon of the ethyl group. Finally all of the hydrogens are equivalent on the 5-carbon and the 2-carbon of the ethyl group. Thus a total of 5 peaks in an H-NMR.

There are 125 million rod cells in one human eye. Each rod cell is sensitive enough to respond to one photon of power P. Knowing that surface area of the retina is 0.00125 m2, and that it takes 20% of the rod cells to become simultaneously active to exhibit a flash of blindness, what is the intensity of light required to blind both eyes? A. 2 billion W/m2 B. 4 billion W/m2 C. 8 billion W/m2 D. 16 billion W/m2

a) We know that the ratio of photons to rod cells is 1:1. With that we can compute the required amount of photons needed by multiplying the total amount of rod cells for 2 eyes, with the percentage required to blind. The required amount of photons are distributed across an entire retina. This will give a photon density of 10 billion per meter squared. Each photon has a power of P. Intensity is power over area, or power times particle density.

Which of the following will least likely affect the length of a protein product? a) Missense mutation b) Frameshift mutation c) Single-base deletion d) Nonsense mutation e) Single-base addition

a) a missense mutation is the substitution of one nucleotide for another in the DNA sequence, resulting in a different resulting amino acid. Essentially, one amino acid is replaced with another. This type of mutation will not alter the overall protein length. A nonsense mutation results in a pre-mature stop codon, causing early termination of the protein product and a shorter protein. Frameshift mutations commonly cause pre-mature stop codons to arise, and at the very least will result in a highly altered protein product that is likely of a different length from the unaltered protein. Single-base addition and deletion will cause frameshift mutations

For a projectile moving in a parabolic path on Earth, which of the following is true? (Ignore wind resistance.) a) The acceleration of the object is constant b) The net force is tangent to the path of the projectile at any given time c) The net force on the object is zero d) The acceleration of the object is zero

a) acceleration is equal to the acceleration due to gravity (about 10 m/s^2) and is constant while the projectile is in the air. The force on the object is given by the product of its mass and gravitational acceleration, and is also constant

Which of the following statements is false concerning alkanes? a) Branching in an alkane raises the boiling point b) Lengthening the carbon chain raises the melting point c) Branching in an alkane raises the melting point d) Lengthening the carbon chain raises the boiling point

a) adding to the length of an alkane carbon chain will increase the molecular weight. This raises both the boiling and melting point. Branching within the alkane will create steric disturbances, making it difficult for molecules to densely pack together. This separates the molecules more, raising the melting point by making it more difficult to form a solid, but lowering the boiling point by making it easier to exist as a gas

A fetus does not breathe inside the womb, and so it must obtain oxygen a different way. What property of hemoglobin allows a fetus to recieve the oxyge it needs to develop? a) Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin. b) Fetal hemoglobin is composed of four subunits while adult hemoglobin is composed of two. c) The partial pressure of oxygen in fetal hemoglobin is always the same as that of its mother. d) The partial pressure of oxygen in fetal hemoglobin is always higher than that of its mother. e) Fetal hemoglobin has a lower affinity for oxygen than adult hemoglobin.

a) fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin. Maternal and fetal blood never mix during pregnancy, but they come close to each other in the placenta. Oxygen diffuses easily to fetal hemoglobin here. The reason fetal hemoglobin has a higher affinity is it is composed of two alpha and two gamma subunits, while adult hemoglobin is composed of two alpha and two beta subunits

Premature ovarian failure can cause early menopause. The failure of ovaries to begin maturation of an egg results in elevated hormone release from the anterior pituitary gland to increase the strength of the maturation signal. Which of the following would be expected to have elevated levels? a) FSH b) estrogen c) calcitonin d) human chorionic gonadotropin (hCG)

a) hCG is produced by the egg after fertilization, so it should not be associated with ovarian failure. Calcitonin is involved in the regulation of calcium levels in the blood and should not be affected either. Since estrogen is produced by the ovaries and is involved in the maturation of the egg, its levels should be lower than normal since the ovaries are not being stimulated by the anterior pituitary. FSH is involved in the stimulation of the follicle (initiation of maturation of the egg) and should be elevated since we are told the anterior pituitary responds by increasing the strength of the maturation signal (i.e. increasing hormone levels).

The acceleration experienced by a block moving down a frictionless plane with an incline of 30°. a) Is constant b) Depends on the height of the plane c) Decreases as the block moves down d) Increases as the block moves down

a) if the object has weight w=mg, the component of the force parallel to the plane is given by wsin(theta) where (theta) is the degree of incline. Using Newton's second law F=ma=mgsin(theta) therefore, the object's acceleration down a frictionless incline is a = mgsin(theta)/m = gsin(theta). since g and theta are constant, the object's acceleration is constant as it travels down the plane

A sound source with a frequency of 790Hz moves away from a stationary observer at a rate of 15m/s. What frequency does the observer hear? The speed of sound is 340m/s. a) 757Hz b) 655Hz c) 775Hz d) 826Hz

a) in this scenario the Doppler effect is described by the following equation fo = fs (v+vo)/(v+vs) using the values from the problem we know that vo is zero and vf is 15. v is 340 and fs is 790Hz fo = 790 Hz (340 m/s + 0m/s)/(340m/s + 15m/s) = 757 Hz

What type of bond is formed in potassium iodide? a) Ionic bond b) Nonpolar covalent bond c) Polar covalent bond d) Polar ionic bond

a) potassium iodide (KI) forms an ionic bond. Potassium and iodine have very different electronegativities. The two atoms would form an ionic bond since ionic bonds form between atoms with a large difference in electronegativity (difference > 1.7 using the Pauling scale will result in an ionic bond)

In saltatory conduction displayed by neurons containing myelinated axons, ion flow takes place at which region of the axon? a) Nodes of Ranvier b) Ion flow does not take place during saltatory conduction c) Myelinated portion of the axon d) Schwann cells

a) saltatory conduction is defined as the method by which action potentials are propagated along axons in myelinated neurons. The method by which they do this is by the generation of action potentials at each node of Ranvier. The only place along the myelinated axon that display ion flow are the nodes of Ranvier. The myelinated portions do not display ion flow, allowing the electrical stimulus to rapidly jump down the axon from one node to the next rather than slowly flow down the full axon length. Schwann cells are types of cell that make up the myelin coated sheath for select neurons

Which hormone is responsible for the physiological changes that occur as a result of long-term stress? a) Cortisol b) Gastrin c) Glucagon d) Epinephrine e) Insulin

a) the body's initial response to stress is initiated by the hormone epinephrine, which raises blood pressure, raises cardiac output, and increases glucose production from stored glycogen. If stress is allowed to persist, the adrenal gland increases its output of cortisol to stimulate glucose synthesis. Insulin and glucagon are secreted by the pancreas. Insulin is secreted in response to high levels of blood sugar while glucagon is secreted in response to low levels of blood sugar. Gastrin is secreated by the stomach and secretion diminishes in times of stress

Two parallel plate capacitors C1 and C2 are arranged in parallel within a 10V circuit. If C1 stores 2C of charge and C2 stores 5C of charge, each over 3 seconds, what is the total capacitance of the circuit? a) 0.7 F b) 1.8 F c) 2.4 F d) 0.2 F

a) the capacitance of any capacitor can be calculated with the formula C = Q/V since the capacitors are arranged in parallel, the voltage drop across each will be equal, and in this case 10V. Adding capacitors in parallel is the same as adding resistors in series, where the total capacitance of the circuit is equal to the sum of all individual capacitors C1 = 2C/10V= 0.2F C2 = 5C/10V = 0.5 F Ceq = 0.2F + 0.5F = 0.7F

Consider the following molecular formulas: Ribose: C5H10O5 Ethyl butyrate: C6H12O2 Chlorophyll: C55H72MgN4O5 DEET*: C12H17ON *The IUPAC name for DEET is N,N-diethyl-meta-toluamide Which of the following is NOT true? a) The combined mass percentage of hydrogen and carbon is ribose is greater than the mass percentage of oxygen b) The molecular formula for DEET is the same as its empirical formula c) Oxygen represents a larger percentage by mass in ethyl butyrate than in chlorophyll d) The empirical formula for ribose is CH2O

a) the molecular formula is the same as the empirical formula if it cannot be reduced by any whole number. Any formula containing a single atom of any given element must be an empirical formula as well. the formula for DEET contains a single atom each of oxygen and nitrogen so it cannot be further reduced and must be an empirical formula the molecular formula for ribose can be reduced by a factor of five making d) correct

The interaction between blood pressure and kidney function in humans requires coordination by the renin-angiotensin-aldosterone system (RAAS). This system involves the dynamic interplay of the kidneys, lungs, and blood vessels to carefully regulate sodium and water balance. A normal human kidney has cells adjacent to the glomerulus called juxtaglomerular cells. These cells sense sodium content in urine of the distal convoluted tubule, releasing renin in response to a low level. Renin is an enzyme that converts angiotensinogen to angiotensin I (AI). AI is converted to angiotensin II (AII) by angiotensin converting enzyme (ACE) in the lung. AII stimulates aldosterone secretion in the zona glomerulosa of the adrenal gland. Aldosterone then acts to upregulate the sodium-potassium pump on the basolateral side of distal tubule epithelial cells to increase sodium reabsorption from the urine, as well as increasing potassium excretion. The passage notes that the RAAS functions at the distal tubule. What is the primary function of the proximal tubule? a) Solute reabsorption and secretion b) Detoxification of filtrate c) Filtration d) Concentration of filtrate e) Transport of urine from the loop of Henle to the collecting duct

a) the proximal tubule is the primary site of solute reabsorption and secretion, modifying the urine after its initial filtration in the glomerulus concentration of the filtrate primarily occurs in the collecting duct, and the distal convoluted tubule transports urine from the loop of Henle to the collecting duct. Filtration occurs in the glomerulus and Bowman's capsule, known together as the renal corpuscle

How much electrical energy is lost per hour in a circuit that has a resistor with a resistance of 300Ω and a voltage source that supplies a voltage of 3V? a) 108J b) 0.06J c) 0.03J d) 216J

a) the question is asking for the amount of energy lost per unit of time; therefore, we need to solve for the poser dissipation. We are given the resistance and the voltage. This means that we use the power dissipation equation in terms of resistance and voltage: P = V^2/R = 3^2/300 = .03W recall that watts is the SI unit for power, but it can also e written as Joules per second. Since we are solving for Joules lost per hour, we need to convert our units: 0.03W = .03J/s x 3600s/hr = 108 J/hr this means that 108J of electrical energy is lost every hour due to power dissipation in the resistor

Diana takes the subway to and from school every day. Her family's apartment, situated in a low-income neighborhood of New York City, is a thirty-minute walk from the subway station. During her trips to the subway, Diana loves to watch people work, play, and socialize. She feels very safe in her community because she trusts the people around her. Diana's mother is having trouble seeing clearly. The lens of her eye appears white and cloudy. Which of the following most likely describes this situation? a) Cataract b) Kinestesis c) Astigmatism d) Conjunctivitis

a) the symptoms describe a "cataract." Cataracts form when a protein coat builds up and cause a white barrier to form that limits vision. It is normally surgically removed. "astigmatism" is a misshapen cornea that can also cause vision problems. "Conjunctivitis" is a disorder that is made evident by the inflammation of the sclera, or white part of the eye. Last, "glaucoma" describes damage caused by the optic nerve, usually by a buildup of excess fluid in the eye

Which of these populations could meet the criteria required for Hardy-Weinberg equilibrium? a) A population of about 100,000 wild cats mate randomly and stay in the same area. Their mutation rate is negligible and their environment contains no factors that select for specific traits. b) A population of over 50,000 elephants routinely travels from the western region of Africa to a more central region to deal with seasonal food supply fluctuations. c) Finches randomly mate on a small island in the Caribbean. These birds eat hard-shelled seeds, so finches with short, strong beaks experience directional selection. d) A group of about 40 swans displays random mating and does not migrate to areas with other swan populations. e) A very large group of people has a near-zero mutation rate, no migration, and a tendency to marry their first cousins.

a) to meet Hardy-Weinberg criteria, a population must be very large (preferably infintite) and exhibit no mutation, no net migration, no natural selection, and no non-random mating. Of the choices, all break one of these criteria except the large population of wildcats

Which of the following best represents the typical onset age for obsessive compulsive disorder? a) 9-25 years old b) 25-45 years old c) 1-9 years old d) Over 45 years old

a) while it may occur in children under five, obsessive compulsive disorder generally presents either in childhood (ages 10-12) or in early adulthood (ages 18-22). onset after age 25 is less common, and onset in middle age is rare

A bacterium has been genetically transformed with human Gene A which consists of approximately 800 nucleotides. During expression, researchers notice that the protein is not being translated; only fragments of approximately 50 amino acids are formed. Genetic sequencing shows there are no nonsense mutations in the gene sequence. Which of the following is a plausible explanation for the observation? a) The bacterium lacks the tRNA that corresponds to the particular codon for the 51st amino acid. b) The bacterial ribosome is incompatible with the human mRNA and cannot properly translate the protein. c) The bacterium is unable to glycosylate the protein, terminating translation early. d) The human gene is too long; bacteria can only synthesize proteins up to approximately 50 amino acids.

a) with the prompt indicating you are looking for the "plausible" answer, this is a strong indication that 3 out of the 4 answers will have something critically wrong with them - not simply their implausibility. (B) is incorrect because the human gene is inserted as a DNA sequence which is then transcribed to mRNA. Nonetheless, the nucleotide composition should be unchanged for a bacterium or human - indeed it is common to use bacteria to synthesize human proteins. (C) is incorrect because although bacteria do not glycosylate proteins, glycosylation does not occur in eukaryotes until after translation has completed - the processes are not coupled. Therefore the inability to glycosylate should have no impact on the ability to translate the protein. (D) is incorrect because there is no reason to assume bacteria have a limit of 50 amino acids for their proteins. (A) is the correct answer because it is the only one left that is plausible. Indeed there are so-called "rare" codons that certain expression organisms lack which can prove troublesome for protein expression. Although you need not have known this fact prior to reading the question, you should be able to deduce it based on the other answer options present.

Which of the following compounds would have the highest boiling point? a) 2-methylhexane b) 2,4-dimethylpentane c) 2,2,3-trimethylbutane d) 2,2-dimethylpentane

a) 2-methylhexane has the most surface area than any of the other molecules because this molecule is the least branched and most linear in structure. These hydrogens undergo weak dipole moment interactions and thus will raise the boiling point as compared with a molecule of the same molecular weight (in terms of carbons) but with a lower surface area.

Which of the following would be expected of the product of the reaction between acetic acid and SOCl2? a) The product will boil at a lower temperature than acetic acid. b) The product will form hydrogen bonds. c) The product will lose its carbonyl. d) The product and acetic acid will be inseparable using distillation.

a) Acetic acid and SOCl2 will undergo a halogenation reaction where Cl will replace -OH, forming acetic chloride. Since chlorine does not form hydrogen bonds, we can rule out (B). Acetic acid does form hydrogen bonds, but the acid halide does not. This suggests acetic chloride will have a lower boiling point. The carbonyl is maintained, making (C) incorrect. The acetic acid and acetic chloride should have notably different boiling points due to the difference in hydrogen bonding, so they should be separable using distillation.

Normal neurodevelopment in children is typically characterized by the acquisition of personal, social, academic, and occupational functioning. These functions are often learned and developed before the child begins primary education. During this period, the child learns social skills and how to control executive functions. Neurodevelopmental disorders involve developmental deficits that are manifested as impairments in normal neurodevelopment. Impairments in intelligence and social skills are often associated with neurodevelopmental disorders, and they frequently occur together. A child and adolescent psychiatrist wanted to further characterize children with neurodevelopmental disorders according to several protocols. The psychiatrist observed all children with any identified impairments of social skills and any associated intellectual disability The psychiatrist noted the following: communication disorder, impairment in attention, impairment in organization, motor disorder, repetitive behaviors, restricted behaviors, or other interests. The child and adolescent psychiatrist concluded that children with repetitive and restricted interests or patterns of behavior often demonstrate impairments in social skills. Some of the children who had restricted interests, repetitive patterns of behavior, and impairments in social skills also had intellectual impairments, language impairments, associated medical conditions, or other associated mental or behavioral disorders. It was found that specifying the individual characteristics of the neurodevelopmental disorders provided the child and adolescent psychiatrist the ability to better describe the diagnosis and associated symptoms to patients and their families. A child and adolescent psychiatrist examined a 7-year-old boy and gave diagnoses of both intellectual disability and neurocognitive disorder. Which of the following clinical and study findings would be inconsistent with giving both diagnoses? a) Stable intellectual disability with Down syndrome b) Loss of previously acquired cognitive skills following head injury c) Increased level of adaptive function deficits following meningitis d) Acute intracranial hemorrhage overlying gray matter heterotopia on computed tomography scan e) Delayed language milestones in the first 24 months of life

a) the neurocognitive disorders are characterized by a loss of intellectual function. Intellectual disability is typically not progressive, but a diagnosis of neurocognitive disorder may be made with intellectual disability when further cognitive disability develops or is lost, e.g. such as may follow infections ("increased level of adaptive function deficits following meningitis" is consistent and can be eliminated) and traumatic brain injury (both "loss of previously acquired cognitive skills following head injury" and "acute intracranial hemorrhage overlying gray matter heterotropia on computed tomography scan" are consistent and can be eliminated). Thus "stable intellectual disability with Down syndrome" is inconsistent with giving diagnoses of both intellectual disability and neurocognitive disorder and is the correct answer choice. All other choices are consistent with the diagnosis of intellectual disability and neurocognitive disorder. Delayed milestones may be seen as early as within the first two years of life in children with severe intellectual disability ("delayed language milestones in the first 24 months of life" is consistent and can be eliminated).

Alcohols can be oxidized to aldehydes, ketones, or carboxylic acids depending on a variety of factors. They can also participate in nucleophilic substitution reactions, facilitated by conversion into a mesylate or tosylate. Why are tertiary alcohols difficult to oxidize? A. There is no hydrogen attached to the carbon with the hydroxyl group B. There is no hydrogen attached to the alpha carbon C. Its hydroxyl group has no polarization D. They are simply inert E. None of the above

a) Alcohol oxidation involves removal of hydrogens so the carbon can instead bind another oxygen. If no hydrogen is present, then a carbon-carbon bond has to be cleaved, which requires a great deal of energy. This, therefore, will only occur under extreme conditions then. Therefore, A is the correct answer. Alpha carbons are only present with a carbonyl carbon, which is not present with an alcohol. Therefore, B is eliminated. The hydroxyl group is still polarized, ruling out C. Tertiary alcohols are still involved in other reactions, like Sn1 reactions. Thus, they are not inert. D is eliminated too.

Which is a form of cell death that involves cell shrinkage? a) apoptosis b) oncosis c) karyorrhexis d) karyolysis

a) Apoptosis is a form of death in a single cell or a small group of cells, and involves cell shrinkage. Oncosis is a term describing cell death following swelling. Karyorrhexis refers to fragmentation of the nucleus during cell death. Karyolysis refers to the process whereby nuclear chromatin dissolves following karyorrhexis.

The process of the breakdown of fatty acid molecules (beta oxidation) in mammalian cells takes place in: A. mitochondria and peroxisomes. B. mitochondria. C. cytosol. D. smooth endoplasmatic reticulum.

a) Beta oxidation occurs in the peroxisomes in plant and yeast cells. In contrast, this vital reaction takes place in mitochondria and peroxisomes in mammalian cells. Peroxisomes are equipped with the appropriate enzymes that can facilitate the break down of very long fatty acid molecules.

Which of the following correctly indicates the response of CD8+ T-cells when activated? a) Secretion of cytotoxic chemicals b) Causing isotype switching c) Presentation of antigens d) Activation of B-cells

a) CD8+ T-cells are largely responsible for the cytotoxic immune response. By releasing toxic chemicals into virally infected cells, CD8+ T-cells are able to kill these cells in an effort to contain viral infections. Isotype switching refers to changes in the isotype of antibody produced, which is not caused by CD8+ cells, eliminating choice (B). Antigens are presented by macrophages, dendritic cells, certain epithelial cells, and some B-cells, eliminating choice (C). B-cells are not activated by cytotoxic T-lymphocytes, eliminating choice (D).

What is the major intermolecular force in the following compound? (CH3CH2)3N a) dipole-dipole b) hydrogen bonding c) London dispersion d) ionic

a) The dipole formed in this molecule allows for the formation of a dipole-dipole interaction. There are no charges strong enough to form an ionic bond, and hydrogen bonds will not form, thus, the dipole-dipole is the strongest intermolecular force.

In the conversion of a ketone to a hemiketal, which of the following changes in the infrared spectrum would indicate completion of the reaction? a) Loss of a strong, sharp peak at 1700 cm-1 and appearance of broad peak around 3200 cm-1 b) Gain of a strong, sharp peak at 3200 cm-1 and loss of multiple smaller peaks at 2600, 1700, and 1400 cm-1 c) Gain of a strong, sharp peak at 2200 cm-1 and loss of a strong, sharp peak at 1700 cm-1 d) A change in the signature of the fingerprint region only

a) There will be a number of important changes to the IR spectrum including gain of new peaks associated with the R-O-R bond, the C-H and C-C bonds of the new alkyl groups, and changes to the fingerprint region. However, where there are predictable and uniform changes will be in the loss of the carbonyl carbon due to its conversion to a hydroxyl group. This change is consistent with a loss of a strong peak around 1700 cm-1 (carbonyl) and the gain of a broad peak around 3200 cm-1 (hydroxyl). You will need to know some of the characteristic peak wavenumbers and shapes of key functional groups for the exam

Signal detection studies measure an individual's ability to detect certain stimuli. They involve exposure to stimuli at varying magnitudes and ask subjects to detect any changes in their perceptual experience of the stimuli (i.e. the just-noticeable difference). Perceiving magnitude differences in stimuli depends on the type of sensory experience (e.g. touch or sound) and is based on proportional rather than absolute amounts. Imagine a hypothetical study that asked participants to perceive changes in amplitude of a sound stimulus. In this experiment, the researchers wanted to know how much the amplitude needed to change in order for an individual to detect a difference. They decided to test the just-noticeable difference at three different amplitudes: low, medium, and high. Participants in each category listened to the initial sound, and then the amplitude was increased or decreased slightly until participants detected a difference. The researchers found that the absolute difference in amplitude that needed to occur in order for participants to detect a difference varied by condition (i.e. low, medium, high amplitude). This observation best illustrates which of the following? a) Weber's law because the just-noticeable difference necessary to detect a change in the magnitude of a comparison stimulus (i.e., the amplitude) is a constant proportion of the initial stimulus. b) Weber's law because the just-noticeable difference necessary to detect a change in the magnitude of a comparison stimulus is always half the magnitude of the initial stimulus. c) Sensory adaptation because as the body is continually exposed to a stimulus, the nerve receptors fire less frequently. d) Sensory adaptation because as the body is continually exposed to a stimulus, the nerve receptors fire more frequently.

a) Weber's law states that the change in a stimulus that will be just noticeable is a constant ratio of the original stimulus. Because the original stimulus changes in each condition (i.e. low, medium, high), the ratio for the just-noticeable difference also changes; therefore, the magnitude necessary to detect a change will vary by condition

There are two models for the operation of the Golgi apparatus in eukaryotic cells. As it is difficult to visualize the operation of cells at the molecular level in real time, scientists typically rely on static electron micrographs to see the morphology of organelles. As a result, the dynamic operation of these organelles can sometimes be unclear. Cisternal Maturation Hypothesis In the cisternal maturation hypothesis, the cisternae of the Golgi apparatus evolve. Proteins leave the endoplasmic reticulum, and enter the cis-Golgi. The cisterna of the cis-Golgi then matures, with its enzymatic contents and internal environment changing as it becomes the medial-Golgi, and, eventually, the trans-Golgi. In this model, the proteins never physically leave their membrane-bound cisternae during their transit across the Golgi. Instead, the entire unit of contents remains within the evolving cisternae. Vesicular Transport Hypothesis In contrast to the cisternal maturation hypothesis, the vesicular transport hypothesis posits that the cis-, medial-, and trans-Golgi cisternae are more static structures. Instead of evolving around their contents, the contents are physically shuttled via vesicular intermediates from each cisterna to the next. In the case of vesicular transport, vesicles are shuttled along microtubules. Motor proteins facilitate this movement, with unique proteins being used for each direction of movement along a microtubule. The Golgi is involved in the packaging of many neuronal transmembrane proteins, including membrane ion channels. Which of the following is true of a normal resting membrane potential? (Note: membrane potential is typically measured relative to the cytosolic face.) a) It is somewhat negative, due to a relatively high permeability via potassium channels b) It is somewhat negative, due to a relatively high permeability via potassium carriers c) It is somewhat negative, due to a relatively high permeability via sodium channels d) It is somewhat positive, due to a relatively high permeability via potassium channels e) It is somewhat positive, due to a relatively high permeability via sodium channels

a) compared to other compounds, the resting permeability of the cell membrane to potassium ions is quite high in most cells. During normal cell metabolism, the sodium-potassium pump moves three sodium ions out of the cytosol, and two potassium ions into the cytosol. The result is a high cytosolic potassium concentration and an efflux of potassium through the permeable membrane it is important to note that the resting membrane potential is set by ion channels, and not ion carriers. The latter will change conformation during translocation of ions, while channels are simply conduits

The combustion of liquid hexane in air at 298K gives gaseous carbon dioxide and liquid water, as shown in this reaction. 2C6H14(l)+19O2(g)→12CO2(g)+14H2O(l) ΔH0f of C6H14(l) is −167.4kJmol. ΔH0f of CO2(g) is−393.5kJmol. ΔH0f of H2O(l) is −285.8kJmol. Calculate the ΔH0rxn for the combustion of hexane liquid hexane at 298K. a) −8384.2kJ/mol b) −9058.6kJ/mol c) 9058.6kJ/mol d) −4194.2kJ/mol e) 8384.2kJ/mol

a) to calculate the delta H reaction the following formula is used. remember that the coefficients of the balanced chemical equation must be included as shown. Also recall that the delta Hf of any pure element is zero delta H reaction = sum of the delta H products minus the sum of the delta H reactants

How many liters of 0.3M HCl can be made from a 2L stock solution of 1.5M HCl? A. 10L B. 12L C. 6L D. 20L

a) M1V1 = M2V2(0.3)(V1) = (1.5)(2)V1 = 10 L

In certain insects, juvenile hormone suppresses metamorphosis from larva to adult. Instead, this hormone allows the young organism to grow in size while remaining in the immature larval stage. Eventually, the juvenile hormone decreases, causing metamorphosis to take place. If the corpora allata, the site of juvenile hormone production and release, is surgically removed an an early larval stage, what is expected to happen? A. A tiny adult will form. B. The larva will continue to grow, and metamorphosis will occur at the normal age. C. The larva will no longer grow or undergo metamorphosis. D. The larva will continue to grow until it looks like a giant, adult-sized larva.

a) No previous knowledge about insects, hormones, or metamorphosis is required. The ability to logically apply the given information is required. If juvenile hormone inhibits metamorphosis, removal of the hormone should cause metamorphosis to occur earlier.

Which reagent would you choose to convert hexan-1-ol to hexanal? A. PCC/CH2Cl2 B. DIBAL/diethyl ether C. KMnO4/aqueous H2SO4/acetone. D. K2Cr2O7/aqueous H2SO4/acetone.

a) Pyridinium chlorochromate (PCC) is a mild oxidant, which converts primary and secondary alcohols to aldehydes and ketones respectively. KMnO4 and K2Cr2O7 are harsher oxidants, and would further oxidize primary alcohols to the corresponding carboxylic acids. Di-isobutylaluminum hydride (DIBAL) is a reducing agents

A researcher conducts an experiment to examine how situational factors influence memory recall. Subjects learn strings of random letters and they are then tested on their ability to recall the information at a later date. One group of subjects takes the memory recall test in the same room where they learned the random letter strings, whereas the other group of subjects takes the memory recall test in an unfamiliar room. In this experiment, the dependent variable is which of the following? a) the type of room b) recall rate c) length of random letter strings d) situational factors

b)

A researcher pumps a known gas into an empty cylinder, compressing the gas, and, as a consequence, increasing the temperature of the cylinder. In order to determine the amount of gas pumped into the cylinder, which of the following methods would be most effective? a) use a pressure gauge and calculate the amount of gas based on the pressure and the known volume b) measure the difference in mass before and after filling c) measure the change in temperature before and after filling d) use an ultrasonic device to measure the density of the gas inside the cylinder

b)

A wave with a wavelength of 10 m and a frequency of 3 x 104 Hz travels across a long field. How long will it take for this wave to pass over 1 km? a) 0.001 seconds b) 0.003 seconds c) 0.09 seconds d) 0.3 seconds

b)

Competent bacteria cells are capable of taking up plasmids. A scientist in a lab intends to amplify a specific plasmid by transforming a competent strain of bacteria with the plasmid in question and then letting the bacteria divide. The scientist can then isolate the bacterial genetic material, which includes now includes the plasmid. The plasmid also encodes a gene for ampicillin resistance (which is not encoded in the competent bacteria cells), allowing transformed bacteria to grow on agar plates containing ampicillin. A negative control is used to determine if a confounding variable is affecting an experiment's results. Negative controls are groups in which we would not expect a result when applying all of the experiment`s conditions except for the independent variable. Which of the following can act as a negative control to ensure that the bacteria that grow on the agar containing ampicillin are transformed bacteria? a) Just distilled water b) Just competent bacteria cells c) Just plasmid d) Just bacterial cells and plasmid

b)

If 209Po underwent alpha decay followed by β- decay, what would be the product? a) 204Pb b) 205Bi c) 209At d) 210Fr

b)

If the index of refraction is equal for two bordering media of differing densities, the angle of refraction of light passing from one medium to the other will be a) greater than the incident angle if the first medium is denser than the second b) equal to the incident angle c) less than the incident angle if the first medium is denser than the second d) the answer cannot be determined with the given information

b)

In a gas, assume that the mass of each molecule is 10-5 kg and each molecule travels at 1 m/s. Utilizing the de Broglie wavelength equation λ = h/(mv), what is the wavelength of each gas particle? Assume that Planck's Constant is h = 7 x 10-34. a) 7 x 1029 m b) 7 x 10-29 m c) 7 x 10-30 m d) 7 x 10-31 m

b)

In a study, subjects were asked to rate how funny cartoons appeared. One group of subjects held a pen crosswise in their lips while making the rating, whereas the other group of subjects held a pen crosswise in their teeth. The subjects holding the pen in their teeth rated the cartoons funnier than the subjects holding the pen in their lips. The independent variable in this study was: a) cartoon rating b) pen position in mouth c) cartoon rating and pen position d) observer bias

b)

Moving a 2 x 10-6 coulomb point charge from point X to point Y in an electric field requires 8 x 10-4 joule of work. The potential difference between points X and Y is approximately a) 4 x 10^-2 V b) 4 x 10^2 V c) 4 x 10^3 V c) 4 x 10^-3 V

b)

The balloon industry is experimenting with different heavier gases which can be used for non-floating balloons. The two gases are labeled gas A and gas B. Gas A is about 9 times heavier than gas B. Gas A was placed in a standard balloon and tested to effusion speed. The gas was found to have a effusion speed of k. What is the expected effusion speed of gas B? Assume that the mass of gas A per mol is M g/mol. a) k/3 b) 3k c) 9k d) k/9

b)

The half-life for the degradation of a new drug in the blood is found to be 8 hours. A patient is administered a dose of 4 ng/dl and has a detection limit of 0.05 ng/dl. Approximately how long will it take for the drug to be undetectable in the blood? a) 8 hours b) 50 hours c) 80 hours d) 160 hours

b)

The index of refraction for a glass ceiling over a football stadium is found to be 2.5. It is approximately 5 m thick. How long does it take light to cross this glass ceiling? a) 5 * 10-7 seconds b) 4 * 10-8 seconds c) 1 * 10-8 seconds d) 5 * 10-9 seconds

b)

Through a lengthy decay process, compound X becomes compound Y. Compound X has 92 protons and an atomic mass of 238. Compound Y has 73 protons and an atomic mass of 198. Which of the following represents a potential decay reaction that could yield compound Y? a) 10 alpha decays b) 5 alpha decays, followed by 1 beta decay, followed by 5 alpha decays c) 10 alpha decays followed by 2 gamma decays d) 5 alpha decays, followed by 1 electron capture, followed by 5 alpha decays

b)

Using the ideal gas law, which of the following statements is true about a closed system? (where n is held constant) a) At constant temperature, an increase in pressure will result in an increase in volume. b) At constant temperature, an increase in pressure will result in a decrease in volume. c) At constant pressure, an increase in volume will result in a decrease in temperature. d) At constant pressure, a decrease in volume will result in an increase in temperature.

b)

What is the enthalpy change (ΔH) of the reaction 2NO + O2 → 2NO2 given the following information: N2 + O2 → 2NO (ΔH = 180 kJ) N2 + 2O2 → 2NO2 (ΔH = 68 kJ) a) 112 kJ b) -112 kJ c) 248 kJ d) -248 kJ

b)

What is the focal length of a concave mirror with a radius of 1 m? a)0.25 m b) 0.5 m c) 1 m d) 2 m

b)

What is the major determinant of the half-life for a radioactive decay? a) The concentration of radioisotope b) The activation energy of the decay c) The temperature d) The difference in mass between the reactant and product

b)

What is the molecular geometry and orbital hybridization of methane? a) trigonal planar, sp2 b) tetrahedral, sp3 c) linear, sp d) trigonal bipyramidal, sp3d

b)

Consider the following half reactions and corresponding reduction potentials: HalfReaction...................................Eo(V) Cl2(g)+2e−→2Cl−(aq)....................+1.36 Ag++e−→Ag(s)...........................+0.80 I2(s)+2e−→2I−(aq).....................+0.54 Pb2++2e−→Pb(s)...................−0.13 Li++e−→Li(s)........................−3.05 Based on the above information, which substance can oxidize I−(aq) to I2(s) ? a) Pb(s) b) Cl2(g) c) Li+ d) Ag(s) e) Pb2+

b) the reduction potential of I2 is +0.54, so the corresponding oxidation potential of I- is -0.54 for a sustance to oxidize this, it must have reduction potential greater than +0.54, so that the sum of the reduction potential of this compounds and the oxidation potential of I- is positive

When a catalyst is added to a chemical reaction, what will be its effect on the energy of the activated complex and on the rate of the reaction? A. The energy of the activated complex will increase, and the reaction rate will decrease. B. The energy of the activated complex will decrease, and the reaction rate will increase. C. The energy of the activated complex and the reaction rate will increase. D. The energy of the activated complex and the reaction rate will decrease.

b) A catalyst lowers the activation energy of a reaction, causing an increase in the reaction rate.

Which of the following hormones is not involved in the female menstrual cycle? a) FSH b) Prolactin c) LH d) Progesterone

b) Although prolactin is involved in stimulating lactation (as well as other, more complex functions), these are not directly part of the menstrual cycle. FSH and LH regulate the growth of the follicle and release of the egg while progesterone supports gestation and prepares for fertilization.

Becoming a college graduate requires hard work and diligence in academics. As such, being a college graduate could be considered a(n): a) ascribed status. b) achieved status. c) master status. d) pigeonholed status.

b) An achieved status is one that is acquired through personal efforts. This is in contrast to an ascribed status, choice (A), in which the status is involuntarily given based on race, ethnicity, gender, family background, and so on. A master status, choice (C), is one that influences all aspects of an individual's life. While being a college graduate is an important aspect of day-to-day life, it does not usually pervade every part of our lives.

Some enzymes require the presence of a nonprotein molecule to behave catalytically. An enzyme devoid of this molecule is called a(n): a) holoenzyme. b) apoenzyme. c) coenzyme. d) zymoenzyme.

b) An enzyme devoid of its necessary cofactor is called an apoenzyme and is catalytically inactive.

After a chemical extraction you are unsure about whether you have any chloride ions in your solution. Which is the best option for testing the presence of chloride in your solution? a) Sodium Nitrate b) Silver Nitrate c) Iron Sulfate d) Ammonium Sulfate

b) Answers A, C, and D would all produce soluble ions with chloride (Sodium, Iron, and Ammonium chloride are all water-soluble). Hence they would not be effective answers to your dilemma. Silver chloride, on the other hand, precipitates and will quickly tell you whether there is chloride in your solution.

Which of the following is the charge on aspartate at a pH of 7? a) -2 b) -1 c) 0 d) +1

b) Aspartate, or aspartic acid, is one of the amino acids with an acidic side chain. At a pH of 7, there are two negative charges (from the dehydrogenated carboxyl group of the amino acid and the dehydrogenated carboxyl group of the R-group) and one positive charge from the amino group. Thus (B) is the correct answer.

Photons and other energy sources can exite electrons into higher energy levels, though these excitations are typically short-lived. X-ray imaging succeeds because different tissue types are differently able to absorb the energy of a photon in order to excite an electron. Suppose an electron falls from n = 4 to its ground state, n = 1. Which of the following effects is most likely? a) A photon is absorbed. b) A photon is emitted. c) The electron moves into a p-orbital. d) The electron moves into a d-orbital.

b) Because the electron is moving into the n = 1 shell, the only subshell available is the 1s subshell, which eliminates choices (C) and (D). There will be some energy change, however, as the electron must lose energy to return to the minimum-energy ground state. That will require emitting radiation in the form of a photon.

Decarboxylation describes the complete loss of the carbonyl group. This is a very common way of getting rid of a carbon from the parent chain. Under heat, 1,3 dicarboxylic acids and beta-keto acids spontaneously decarboxylate. What is the resulting product (in addition to carbon dioxide)? A. An enol B. A keto C. An aldehyde D. An alcohol E. None of the above

b) Decarboxylation describes the complete loss of the carbonyl group. This is a very common way of getting rid of a carbon from the parent chain. Under heat, 1,3 dicarboxylic acids and beta-keto acids spontaneously decarboxylate. What is the resulting product (in addition to carbon dioxide)?

Tetrodotoxin (TTX) is found in pufferfish, which are enjoyed predominantly in Japan. TXX blocks Na+ channels, blocking neurotransmission. Blockage of the phrenic nerve results in paralysis of the diaphragm and a cessation of breathing. This is fatal. What is a consequence of neurotransmission? A. It is bi-directional B. It is uni-directional C. It is not subject to inhibitory control D. Summation does not occur E. None of the above

b) Explanation: Think about the anatomy of a neuron and the steps of propagation. Signals are transmitted through the cell body via dendrites. Then the axon hillock integrates the incoming signals and if threshold is surpassed, an action potential is initiated. Propagation then transfers the signal to other neurons via neurotransmitters. Therefore, this occurs in a uni-directional manner. Moreover, refractory periods, in which a neuron cannot be restimulated (absolute refractory period) or needs greater than usual signal to do so (relative refractory period), reinforce the uni-directional nature of neurotransmission. This eliminates A and validates B. C is simply false since neurons receive inhibitory signals and summation definitely occurs, both temporally and spatially, eliminating D as well.

A 50N crate is set in motion. The coefficient of static friction is 0.50 and the coefficient of kinetic friction is 0.20. What is the difference between the force needed to initiate motion and the force needed to maintain motion? A. 10 N B. 15 N C. 25 N D. 125 N

b) Finitiating= ( us)N ; And Fmaintaining= ( uk)N Fi- Fm= (us- uk)N = (0.50 - 0.20)(50 N) = 15 N

Condensation of water in the atmosphere requires a nucleation point for clouds. Which of the following substances functions as a most effective nucleation point? a) ozone b) dust c) NOx d) sand

b) Gasses will not serve as nucleation points for the condensation of water, thus 'a' and 'c' are incorrect. Sand is too large of a substance and is rarely found airborne, so it will not serve as a nucleation point. Thus, dust, with its small size and abundance in the atmosphere will serve as a nucleation point.

A chemist runs a reaction that results in more stable bonds and orderly arrangement of the products versus the reactants. Which of the following is true of this reaction? A. The enthalpy and entropy changes are positive B. The enthalpy and entropy changes are negative C. The enthalpy change is positive, and the entropy change is negative D. The enthalpy change is negative, and the entropy change is positive

b) If the products have more stable bonds, that means they have less energy, and that energy must have been released, hence the change of enthalpy is negative. If the products are in a more orderly arrangement than the reactants, then the entropy decreased; thus the change in entropy is also negative, and the only answer left is B.

How many H-NMR peaks would an individual expect to see in chlorobenzene? a) 2 b) 3 c) 5 d) 6

b) If we begin the numbering of the carbons at the carbon attached to the chlorine, then we see that the hydrogens attached to 2 and 6 are chemically the same. This holds true for 3 and 5. Thus there are only 3 chemically distinct hydrogens: that on C-2 and C-6, the ones on C-3 and C-5, and the one on C-4.

Which of the following trends regarding healthcare disparities has NOT been documented? a) Females are more likely to be insured than males. b) Primary care use is more likely among males than females. c) Low-income individuals have more difficulty accessing care than high-income individuals. d) LGBT individuals have more barriers to healthcare than heterosexuals.

b) In comparison to females, males visit primary care doctors less frequently. All of the other trends listed here have been documented.

A 28-year-old male comes to a clinic concerned that he has pancreatic cancer. Review of his medical records shows that this is the fourth time in the past year that the patient has appeared for medical attention. No identifiable medical problem is found. When confronted with this history, he confesses that he feels relieved after being told that all of the tests are negative, but soon becomes worried again that he has cancer. Based on the information, the most likely diagnosis for this patient would be: a) major depressive disorder. b) illness anxiety disorder. c) conversion disorder. d) narcissistic personality disorder.

b) In illness anxiety disorder, the person is preoccupied with fears that he has—or will come down with—a serious disease, and these fears continue even after medical exams and tests have returned negative results.

Prolonged vitamin B12 deficiency can be associated with subacute combined degeneration of the spinal cord. Patients with this disease have difficulty walking because they lose the ability to feel where their feet are in space. This represents a loss of: a) vestibular sense. b) kinesthetic sense. c) parallel processing. d) feature detection.

b) Kinesthetic sense, or proprioception, refers to the ability to tell where body parts are in three-dimensional space. The sensors for proprioception are found predominantly in the muscles and joints. Loss of vestibular sense, choice (A), would also cause difficulty walking, but this would be due to a sense of dizziness or vertigo, not an inability to feel one's feet.

A solution is made with an unknown solute in 5L of water. This solution is found to have a molality of 15 molal. What is the molar mass of the compound if 300g of the solute are dissolved in the solution? a) 1 g/mol b) 4 g/mol c) 26 g/mol d) 40 g/mol

b) Molality is defined as moles of solute divided by kilograms of solvent. 5L of water is equivalent to 5kg of solvent. If x is the number of moles of solute, we know that 15 mol/kg = x/5kg thus x = 75 mol. We know that 300g equate to 75 mol, thus the molar mass is 4 g/mol. Thus (B) is the correct answer.

The formation of α-d-glucopyranose from β-d-glucopyranose is called: a) glycosidation. b) mutarotation. c) enantiomerization. d) racemization.

b) Mutarotation is the interconversion between anomers of a compound. Enantiomerization and racemization, choices (C) and (D), mean the same thing as each other: the formation of a mirror-image or optically inverted form of a compound. Glycosidation, choice (A), is the addition of a sugar to another compound.

Which of the following is/are function(s) of NADPH in the cell? I. Antimicrobial resistance via bacterial destruction by bleach within lysosomes. II. Involvement in the production of the precursors to steroid hormones. III. Functional carriage of energy across organelle membranes for use within the mitochondria a) I only b) I and II only c) II and III only d) I, II, and III

b) NADPH has three primary functions: involvement in biosynthesis of lipids and cholesterol (the precursor to steroid hormones), production of bactericidal bleach in the lysosomes of certain white blood cells, and maintenance of a supply of reduced glutathione for protection against free radical damage. Energy carriage is an important function of NADH, not NADPH.

In most cases, neurotransmitters result in the propagation of a) neurotransmitter gradient through the axon b) action potential c) neurotransmitter receptor movement from one end of a neuron to the other d) propagation of a longitudinal wave along the myelin sheath

b) Neurotransmitters almost always stimulate response in neurons by propagating action potentials down axons.

In proton NMR spectroscopy, which compounds or functional groups show a characteristic peak in the range 9-10 ppm? A. halogenated alkanes B. aldehydes C. alcohols D. aromatic compounds

b) Nuclear magnetic resonance (NMR) is concerned with the magnetic properties of certain nuclei. Anything that removes electron density from around a nucleus deshields it and shifts the absorption to higher frequency. The more electronegative the atoms that are attached to the nucleus, the higher the absorption frequency. Thus, NMR is able to provide information on the types of functional groups present as each has a characteristic chemical shift range. Aldehydes have a very characteristic shift of 9-10 ppm.

What is the Vant Hoff factor of the molecule Li3PO4? a) 2 b) 4 c) 3 d) 1 e) 5

b) The Vant Hoff factor indicates how many particles a solid produces when dissolved in solution. When Li3PO4 dissolves in solution, there are three Li+ molecules and one molecule of PO4^-3. The vant Hoff factor is equal to the sum of molecules: 3Li+ + 1PO4^-3 = 4 total ions

Ammonium sulfate precipitation involves the addition of the highly-soluble salt ammonium sulfate to raise the ion concentration until proteins differentially precipitate based on their solubility at high ion concentrations. This technique is most similar to: a) mass spectrometry. b) column chromatography. c) electrophoresis. d) PCR.

b) PCR is a technique used on nucleic acids, not proteins; thus (D) can be eliminated. (A) can be eliminated because mass spectrometry allows for characterizing the structure and sequence of a molecule or protein, but is not itself a protein separation tool. Electrophoresis allows for the separation of proteins by their size, which is not an important factor in differential solubility in high ion concentrations. Thus (C) can be eliminated. (B) is correct because column chromatography can separate proteins based on their ionic profiles and their hydrophobic nature which is the property manipulated by increasing the ion concentration.

Under what circumstances would a methyl group appear as a doublet in H1-NMR? a) Deuterium is present on one of the hydrogen atoms in the methyl group. b) There is only one hydrogen atom attached to the carbon adjacent to the methyl group. c) There are two hydrogen atoms attached to the carbon adjacent to the methyl group. d) There are two carbon atoms attached to the carbon adjacent to the methyl group.

b) Peak splitting, which is responsible for doublets, triplets, etc. is based on the number of hydrogen atoms attached to adjacent carbon atoms. A methyl group can only be attached to one carbon atom, so the number of hydrogen atoms attached to that carbon atom determines the peak splitting of the methyl group. Normally a singlet would appear with no hydrogen atoms on the adjacent carbon. An additional peak appears for each hydrogen atom. Since a doublet is present, only a single hydrogen atom is present, making (B) the correct answer.

Which of the following is NOT a product of eukaryotes? a) glycosylated proteins b) peptidoglycan c) cellulose d) chitin

b) Peptidoglycan is only present in prokaryotic cell walls. Cellulose and chitin are both products of certain eukaryotic pathways including fungi and plants. Glycosylation requires complex protein processing pathways which eukaryotes commonly employ.

The site of oxidative metabolism in eukaryotes is the mitochondrion, which utilizes specialized membranes in order to generate ATP. What is the analogous structure in prokaryotes used to carry out oxidative metabolism? a) outer membrane b) plasma membrane c) nuclear membrane d) cell wall

b) Prokaryotes will use proton gradients across their plasma membranes to drive the majority of ATP synthesis that is analogous to the ATP synthesis carried out in the mitochondria of eukaryotes.

.Using the ideal gas law, which of the following statements is true about a closed system? (where n is held constant) a) At constant temperature, an increase in pressure will result in an increase in volume. b) At constant temperature, an increase in pressure will result in a decrease in volume. c) At constant pressure, an increase in volume will result in a decrease in temperature. d) At constant pressure, a decrease in volume will result in an increase in temperature.

b) Recall that in a closed system, the moles of gas and the ideal gas constant can be reduced to yet another constant. This would make PV/T = k. Consider that in (b), since T is held constant, it can be included in k; you are now left with PV = k. If P goes up, then V must go down in order to keep k constant.

Within towns, there are neighborhoods that are known for their ethnic, racial, and economic characteristics. This is an example of: a) Environmental justice b) Residential segregation c) Global inequalities d) Social stratification

b) Residential segregation is the dividing of a population based upon housing and neighborhoods. Residential segregation can be either purposeful or unintentional. Common reasons for residential segregation are income, class, race, ethnicity, or individual preference.

Saltatory conduction functions to a) Increase potassium concentrations in surrounding neurons b) Increase conduction velocity c) Prevent neurons from constant hyperpolarization d) Control wave propogation and direction

b) Saltatory conduction occurs due to the myelination of neurons. The myelin allows for depolarization at one end of the node to result in depolarization at the other end. This allows for the action potentials to actually jump from node to node, which functionally increases conduction velocity.

Harley-Davidson, as you likely know, is an American motorcycle manufacturer founded in Milwaukee Wisconsin in 1903. It is one of only two American motorcycle manufacturers to survive the Great Depression. Which of the following would be an example of semantic memory? A. Having the ability to drive a motorcycle B. Knowing the parts of a motorcycle C. Remembering the experience of first learning to ride a motorcycle D. Associating a Harley-Davidson with other motorcycles in a semantic network E. None of the above

b) Semantic memory is a type of long-term memory, specifically the recall of facts, instead of experiences or skills. This eliminates both A and C. Moreover, semantic networks are associations of similar concepts aimed to aid in their retrieval. This rules out D as well. We are left with B as the correct answer.

which area of the body would not be expected to have stratified squamous epithelium? a) tongue b) small intestine c) esophagus d) skin

b) Stratified squamous epithelium is primarily associated with protection of the body, and is found in areas that commonly encounter stress. These areas include the skin, the tongue, and the esophagus. The small intestine is associate with absorption and is lined with simple columnar epithelium

Which of the following describes a relationship between two organisms where one party benefits and there is no effect for the other? a) symbiosis b) commensalism c) parasitism d) mutualism

b) Symbiosis is an umbrella term used for any long-term living relationship between two species. Parasitism benefits one and harms the other. Mutualism benefits both. Commensalism is a relationship where one species benefits while the other neither gains nor loses. Thus the correct answer is (B).

In the menstrual cycle, the LH surge involves a rapid and dramatic spike of luteinizing hormone. This surge is immediately followed by which of the following? a) menstruation b) ovulation c) pregnancy termination d) fertilization

b) Termination of pregnancy is not a part of the menstrual cycle, so this can be ignored. (D) is also incorrect since fertilization is not a direct part of the cycle as well. Menstruation occurs at the end of the luteal phase, but the LH surge occurs just before the luteal phase; in fact it helps to initiate it. Ovulation is initiated by the LH surge, which then results in the start of the luteal phase making (B) the correct answer.

If you consider the possible microstates in a chunk of ice, it is easy to imagine them as very limited. As the ice melts, the freedom of movement of the water molecules increases. Since the temperature is unchanged, and thus the kinetic energy is unchanged, the energy is dispersed over a larger number of microstates. In other words, the entropy has increased. What are the appropriate units for entropy? A. J^2/ mol x K B. J/ mol x K C. kJ/ mol x C D. J/ mol^2 x K E. None of the above`

b) The appropriate units are listed in B. The equation for entropy is : ΔS=QrevT, with Qrev being equal to the heat gained or lost in a reversible process and T being the temperature in kelvin.

A bar 8 meters long is placed on a pivot 2.0 meters from the lighter end of the bar. The center of gravity of the bar is located 2.0 meters from the heavier end. If a 500 N weight on the light end balances the bar, what must be the weight of the bar? A. 125 N B. 250 N C. 500 N D. 1000 N

b) The center of gravity occurs 4.0 m from the pivot point. At equilibrium: (2.0 m)(500 N) = (4.0 m)(w) w = ½ (500N) = 250 N

Two pipes have cross-sectional area X and connect to become a single pipe, called pipe P. The output flow in pipe P is quadruple the flow of that in the two pipes and is measured as F. What is the cross-sectional area of pipe P? a) A b) A/2 c) A/4 d) A/8

b) The continuity equation states that the product of area and flow velocity is preserved across a system. We can set the cross-sectional area of pipe P to be Y. Thus A(F/4) + A(F/4) = YF, thus AF/2 = YF, thus Y=A/2. Thus (B) is the correct answer.

What is the most correct definition of competitive inhibition? A. Another enzyme completes the same reaction and uses the available reactant B. An inhibitor binds directly to the active site and prevents the reactant from binding C. A metal cofactor prevents the binding of the reactant by binding at the active site D. An inhibitor binds to the enzyme at a binding site, and prevents the enzyme from catalyzing the reaction

b) The correct answer is B. Metal cofactors and ATP are often used to help boost enzyme activity, and are not competitive inhibitors. Non-competitive inhibition(D) occurs when an inhibitor is able to prevent the enzyme from binding with the reactant by binding to the enzyme at a site away from the active site, and change the enzyme's conformation so it cannot bind to the reactant. Competitive inhibition occurs when the inhibitor competes directly with the reactant at the active site, and this substrate takes the place of the reactant and prevents the reaction from occurring.

The rough endoplasmic reticulum is so named because of ribosomes on its membrane. Which of the following statements best describes the way in which these ribosomes translate proteins? a) From the cytosol, into the intermembrane space of the endoplasmic reticulum b) From the cytosol, into the lumen of the endoplasmic reticulum c) From the intermembrane space of the endoplasmic reticulum, into the cytosol d) From the lumen of the endoplasmic reticulum, into the cytosol

b) The endoplasmic reticulum does not have an intermembrane space, thus A and C are false. Ribosomes attached to the membrane of the endoplasmic reticulum translate proteins directly into the lumen of the endoplasmic reticulum through porins. Recall that mRNA does not enter the lumen of the endoplasmic reticulum; it remains in the cytosol, thus, proteins will be translated from the cytosol into the lumen.

In fruit flies with the curly wing mutation, the wings will be straight if the flies are kept at 16 degrees Celsius. The most probable explanation for this is that a) fruit flies with curly wings cannot survive at high temperatures b) the environment influences wing phenotype in these fruit flies c) high temperatures increases the rate of mutations d) wing length in these fruit flies is directly proportional to temperature

b) The environment influences the expression of many genes. For example, identical twins, with identical DNA, may look different from each other because of the different environmental influences.

Why is the α-anomer of d-glucose less likely to form than the β-anomer? a) The β-anomer is preferred for metabolism. b) The β-anomer undergoes less electron repulsion. c) The α-anomer is the more stable anomer. d) The α-anomer forms more in L-glucose.

b) The hydroxyl group on the anomeric carbon of the β-anomer is equatorial, thereby creating less steric hindrance than the α-anomer, which has the hydroxyl group of the anomeric carbon in axial position.

The myelin sheath is composed of which of the following? a) Na and K channels and pumps b) The plasma membrane of Schwann cells c) Nodes of Ranvier d) Soma

b) The myelin sheaths of neurons are composed of Schwann cells separated by the Nodes of Ranvier.

How does the inner mitochondrial membrane differ from the outer mitochondrial membrane? a) The inner mitochondrial membrane is more permeable and lacks cholesterol. b) The inner mitochondrial membrane is less permeable and lacks cholesterol. c) The inner mitochondrial membrane is more permeable and has cholesterol. d) The inner mitochondrial membrane is less permeable and has cholesterol.

b) The outer mitochondrial membrane is very permeable while the inner membrane is highly impermeable. The inner mitochondrial membrane is unique within the cell because it lacks cholesterol.

A double-stranded RNA genome isolated from a virus was found to contain 15% uracil. What percentage of guanine should exist in this virus's genome? a) 15% b) 35% c) 70% d) 85%

b) The percentage of uracil must equal that of adenine due to base-pairing. This accounts for 30% of the genome. The remaining 70% must be split evenly between guanine and cytosine, so they each account for 35% of the genome.

The rate at which a chemical reaction occurs is dependent on many factors. Which of the following will increase the rate of reaction? A. Decreasing the temperature. B. Adding a catalyst. C. Decreasing the concentration of a reactant in solution. D. Decreasing the partial pressure of a reactant gas.

b) The rate at which a chemical reaction occurs is increased by increasing the temperature, adding a catalyst, increasing the concentration of a reactant in solution, increasing the partial pressure of a reactant gas and increasing the surface area of a reactant solid. Catalysts increase the rate of reaction by providing an alternative way for the reaction to continue with a lower activation energy, thus making the reaction easy to occur under any given conditions.

A MCAT book weighing 40 N is held in contact with the ceiling of a room by an upward force of 50 N. What is the magnitude of the normal force exerted by the ceiling on the book? A. 0 N B. 10 N C. 50 N D. 90 N

b) What are the forces on the book? The weight, 40 N, and the normal force, N are downward forces, and the only upward force is our 50 N push. Since the bloc k is not accelerating vertically, the net vertical force must be zero. Therefore, 40 + N must be 50, which means N = 10 N.

A cobalt electrode is immersed in 1.0M Co2+ and a lead electrode is immersed in 1.0 M Pb2+. Given are standard reduction potentials. Co(2+) + 2e- -> Co ; E(reduction)= -0.28 V Pb(2+) + 2e- -> Pb ; E(reduction)= -0.13 V Which of the following describes the cell? A. E(cell) = -0.15, galvanic B. E(cell) = 0.15 V, galvanic C. E(cell) = -0.41 V, electrolytic D. E(cell) = 0.41 V, galvanic

b) The standard electrode potential E(cell) for a cell is found using the equation: E(cell) = E(oxidation) + E(reduction) In this case, lead will be reduced because it has a higher reduction potential than cobalt. This means that cobalt is being oxidized. Remember that on the MCAT, you will always be given standard reduction potentials, so if we need to find an oxidation potential, we simply switch to the negative reduction potential. Our equations should now look like this: Co -> Co2+ + 2e- ; E(oxidation)= +0.28 V Pb2+ + 2e- -> Pb ; E(reduction)= -0.13 V Thus, using the first equation, we arrive at E(cell) = (+0.28 V) + (-0.13 V) = 0.15 V Remember that if E(cell) > 0, the reaction is spontaneous and happens in a galvanic cell. (The opposite is a non-spontaneous, electrolytic cell). Also, lead cobalt batteries were used in some of the first electric cars!

Which of the following is NOT true of the different kinds of RNA in eukaryotes? A. They are single stranded molecules. B. They all contain codons. C. They may contain guanine and/or uracil. D. They all elongate from the 5′ to 3′ direction.

b) There are 3 types of RNA: (1) ribosomal RNA (rRNA); (2) messenger RNA (mRNA) and (3) transfer RNA (tRNA). RNA is a single-stranded polymer made up of four bases, namely uracil, adenine, guanine and cytosine. Only mRNA can contain a codon, a genetic code consisting of three base pairs that can be translated by the cellular machinery into an amino acid during protein synthesis. RNA elongates elongates from the 5' to 3' direction using a DNA strand with the opposite orientation as a template for transcription.

Aluminum resides in the boron group, with the symbol Al. It is a silvery-white, soft, nonmagnetic, and ductile metal. It makes up about 8% of the earth's crust, by mass. It is the third most abundant element after oxygen and silicon. The following reaction demonstrates what? 3AgO3 + 2 Al -> 3 Ag + Al2O3 A. A double displacement reaction B. Reduction by aluminum C. Oxidation by aluminum D. A combination reaction E. None of the above

b) This is actually a single displacement reaction, with the silver in silver oxide being replaced by the aluminum to form aluminum oxide. This, by necessity, makes it an oxidation-reduction reaction as well. Silver goes from the +6 oxidation state to neutral, while aluminum changes from neutral to the +3 oxidation state. This means silver is reduced, since it gains electrons, and aluminum is oxidized, since it loses electrons. Moreover, since aluminum is oxidized, this makes it the reducing agent. Ultimately, B is correct. For completion sake, combination reactions take on the form A + B -> AB, which is not the case here.

Certain viruses lack 5' caps on their mRNA sequences. Which of the following answers explains one of the ways in which such viruses produce their proteins? a) They carry their own ribosomes which do not need 5' caps in order to initiate translation b) They use Internal Ribosomal Entry Sites (IRES) which allow for the assembly of cellular ribosomes to initiate translation c) They carry out protein synthesis prior to infection; the mRNA is incorporated into the host nucleic acids in dormancy d) They initiate translation from the 3' polyA tail instead of the 5' cap to avoid the problem.

b) Translation occurs in the 5' to 3' direction, hence (D) is incorrect. Protein synthesis is essential for the construction of new virions which can only happen inside the host cell since viruses are obligate intracellular parasites. Hence, (C) is incorrect. Viruses do not carry their own ribosomes into host cells as they exploit this mechanism from the host. Hence, (A) is incorrect. Many viruses employ IRES binding sites including poliovirus.

If an individual displays behaviors consistent with trichotillomania (i.e. hair-pulling), then he or she would be classified under which of the following behavioral disorder subsets? a) Autism spectrum b) Obsessive-compulsive spectrum c) Anxiety disorder spectrum d) Bipolar spectrum e) None of these

b) Trichotillomania is associated with irresistible urges to perform unwanted repetitive behavior, which falls under the obsessive-compulsive spectrum. Although the disorder may cause anxiety to an individual, it does not fit on the anxiety spectrum of behavioral disorders. The autism and bipolar disorder spectrums do not include behaviors or characteristics that are associated with trichotillomania

An individual's thyroid levels are checked by their physician and it is found that the individual's T4 levels are markedly low. This could reflect: I. overproduction of TSH II. underproduction of TSH III. deficient production by the thyroid gland a) III only b) II and III only c) I and III only d) I, II and III

b) Underproduction of TSH by the anterior pituitary or deficient production of thyroid hormone by the thyroid gland would result in decreased T4 levels. Thus (B) is the correct answer.

A whistle of frequency 750 Hz is blown on an truck moving east at 20 m/s. What approximate frequency sound would a stationary person standing west of the truck hear? a) 650 Hz b) 700 Hz c) 750 Hz d) 800 Hz

b) Using the equation for the doppler effect, we know that the frequency = 750 * (340/(340+20)) = 750 * (340/360) which is approximately 700 Hz. Thus (B) is the correct answer.

Treatment of methane with Cl2 at 450 °C produces a mixture of chlorinated products including CH3Cl, CH2Cl2, CHCl3, and CCl4. Distillation is an effective technique for separating the products because: a) the products are all miscible with each other b) the boiling points of the products are distinct and sufficiently different from each other to be separated c) the products are all similar in size and can be isolated together d) the products all boil at or below room temperature

b) We can quickly eliminate (D) because it is simply false; even if it were true, it would not justify why distillation is effective, since the products could in theory all have very similar boiling points below room temperature, making them difficult to separate. (A) is incorrect since miscibility is not a key standard for distillation efficacy; as long as two miscible compounds have similar boiling points, they will be difficult to distill. (C) is incorrect as the compounds are not all of similar size and their ability to be isolated together is not relevant. (B) is the correct answer since the differences in size and polarity between the molecules allows for sufficiently different boiling points such that they can be separated. It is the only option that properly justifies the observation.

Which of the following correctly lists the ions in order from smallest to largest? a) S2-, Cl-, Ca2+, K+ b) Ca2+, K+, Cl-, S2- c) Cl-, S2-, Ca2+, K+ d) S2-, Cl-, K+, Ca2+

b) What each of the ions listed have in common is that they have the same number of electrons. Therefore, the smallest ions will have the most protons, because the protons will pull the electrons closer to the nucleus. Similarly, the largest ions will have the fewest protons. Therefore, the smallest ion will be Ca2+ because it has the largest atomic number and thus has the most protons. Similarly, S2- has the fewest protons and is thus the largest of the ions. The answer directly follows.

Some people with anxiety disorders respond to stress by hyperventilating. It is recommended that these people breathe into a paper bag and then re-breathe this air. Why is this treatment appropriate? a) Hyperventilation causes an increase in blood carbon dioxide, and breathing the air in the bag helps to readjust blood levels of carbon dioxide. b) Hyperventilation causes a decrease in blood carbon dioxide, and breathing the air in the bag helps to readjust blood levels of carbon dioxide. c) Hyperventilation causes an increase in blood oxygen, and breathing the air in the bag helps to readjust blood levels of oxygen. d) Hyperventilation causes a decrease in blood oxygen, and breathing the air in the bag helps to readjust blood levels of oxygen.

b) When people hyperventilate, their respiratory rate increases. When the respiratory rate increases, more carbon dioxide is blown off. This causes a shift to the left in the bicarbonate buffer equation, and the blood becomes more alkaline. Breathing into the bag allows some of this carbon dioxide to be returned to the bloodstream in order to maintain the proper pH.

Which of the following is true regarding a nephron? a) Nephrons are only found in the adrenal medulla b) Nephrons create urine, but they cannot store urine c) Filtration begins in nephrons' capillary beds, called the collecting duct d) A nephron is the functional unit of a neuron

b) a nephron is the functional unit of the kidneys. It is the site of filtration, secretion, and reabsorption (processes essential for urine production). Nephrons contain several structures that facilitate the proper excretion of waste through urine. A nephron contains structures that are found in both the adrenal medulla (inner region) and the adrenal cortex (outer region) of the kidneys; therefore, a single nephron spans both the adrenal medulla and the adrenal cortex. The first step in urine production occurs at the capillary eds of the nephrons. Blood arrives at these capillary bed, known as the glomerulus, and initiates filtration. Filtration is the process by which potential waste products in the blood are filtered into the nephron, where they will utlimately become urine. Remember that nephrons are the site of urine production; they do not store the urine. Once complete, urine exits the kidneys and is stored in the bladder. The bladder stores urine until it reaches the maximum capacity, causing smooth muscles around the organ to stretch. Once this maximum is reached the individual feels the urge to urinate, and the urine is excreted via the urethra

Which division of the nervous system controls the dilator pupillae and is known as the iris dilator muscle? a) The parasympathetic division of the autonomic nervous system b) The sympathetic division of the autonomic nervous system c) The sensory division of the peripheral nervous system d) The somatic division of the peripheral nervous system

b) control of the muscles responsible for dilation of the pupil is mediated by the sympathetic division of the autonomic nervous system. During states of fear, sexual arousal, or heightened attention, the pupil will dilate due to the stimulation of the dilator pupillae, or iris dilator muscle

Which enzyme is involved in protein digestion? a) Bile b) Pepsin c) Chyme d) Salivary amylase e) Nucleases

b) digestion of proteins begins in the stomach. The low pH of the stomach converts pepsinogen into pepsin, which is then used to break down proteins

Gas A is noted to diffuse at triple the rate of a second gas, gas B. This implies that: a) Gas A has triple the mass of gas B. b) Gas B has greater than triple the mass of gas A. c) Gas A is more dense than gas B. d) Gas B has a lower condensation point than gas A.

b) for purposes of the MCAT, it is only necessary to understand the relationship between gas diffusion and the mass of the gas. Per Graham's law, the ratio of the rates of diffusion is inversely related to the square root of the molar masses of the molecules. In this example, gas B must have a molar mass 9-fold that of gas A to result in triple the diffusion of gas A. Thus (B) is the correct answer.

Researchers are studying a disease that causes neurological deficits in humans. They have identified the disorder as autosomal dominant, but notice that about 20% of people with the dominant disease allele do not express any of the associated neurological impairment. What genetics term explains this phenomenon? a) Degeneracy of the genetic code b) Reduced penetrance c) Variable expressivity d) Sex-linked interitance e) Codominance

b) in this example, some individuals with a certain genotype do not express teh expected phenotype (symptoms of the disease) at all. The only term that properly describes this effect is reduced penetrance. Penetrance refers to the percent of individuals with a specific genotype who express the associated phenotype. In most common examples given in genetics courses, autosomal dominant diseases are 100% penetrant, meaning that all individuals with one disease allele will show symptoms to some extent. Here, however, the disease appears to show 80% penetrance one term often confused with penetrance is expressivity. This refers to the extent that the phenotype is expressed, and is only applicable when penetrance is 100%. If all of the individuals showed symptoms of the disease, but some showed slightly different defects than others, the disease would have variable expressivity. The other answer choices refer to unrelated genetics concepts

People in their late teens and twenties who have incoherent and disorganized speech, hallucinations, and delusions are exhibiting the symptoms of __________. a) generalized anxiety disorder b) schizophrenia c) bipolar disorder d) impulse control disorders e) social phobias

b) people with schizophrenia have hallucinations, delusions, and difficulty concentrating. Symptoms of schizophrenia typically begin to appear in the late teens and twenties. Social phobias involve fear of being embarrassed in social situations. The most common is fear of public speaking. People with generalized anxiety disorder are frightened of something but are unable to speak about a specific fear. They develop physical fear reactions. Alterations of episodes of depression with episodes of mania is called bipolar disorder. The inability to resist and impulse to perform an action that is harmful to the individual or to others is an impulse control disorder. Examples are kleptomania and pyromania

Substances for which pure water would not be an efficient solvent are __________. a) those that have large dipole moments b) those with evenly dispersed electrons c) those that tend to form hydrogen bonds d) those that have high charge densities

b) since water is polar, it dissolves substances that have electrostatic charge due to electron arrangement. All of the answer choices describe molecules that would have positive and negative components except those with evenly dispersed electrons. This describes a nonpolar molecule, which would not dissolve in water

The Gram stain distinguishes what type of organisms? a) Pathogenic bacteria versus nonpathogenic bacteria. b) Bacteria with a single membrane and a thick layer of peptidoglycan versus bacteria with two membranes and a thin layer of peptidoglycan. c) Bacteria with a cell wall versus bacteria without a cell wall. d) Bacteria versus archaea.

b) the Gram stain (Gram positive vs. Gram negative) allows visual discernment of bacteria that either retain crystal violet or do not. Bacteria retaining crystal violet have very thick layers of peptidoglycan and a single membrane while bacteria that do not retain crystal violet but retain the counterstain safranin generally have an outer membrane along with the plasma membrane and thin layers of peptidoglycan. Certain cells will stain Gram negative despite not having these parameters, but nonetheless the Gram stain is intended to distinguish between these types of bacteria.

The anterior pituitary is responsible for secreting all of the following hormones except __________. a) Thyroid-stimulating hormone b) Vasopressin c) Follicle-stimulating hormone d) Adrenocorticotropic hormone

b) the anterior pituitary is responsible for secreting hormones into the blood stream, once their respective releasing factors from the hypothalamus arrive through the hypothalamus-pituitary portal system. The anterior pituitary releases growth hormone, adrenocorticotropic hormone, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing-hormoe, and prolactin the posterior pituitary is under neuronal control and releases vasopressin (antidiuretic hormone) and oxytocin

Carbonic anhydrase is an important enzyme that allows CO2 and H2O to be converted into H2CO3. In addition to allowing CO2 to be dissolved into the blood and transported to the lungs for exhalation, the products of the carbonic anhydrase reaction, H2CO3 and a related compound HCO3-, also serve to control the pH of the blood to prevent acidosis or alkalosis. The carbonic anhydrase reaction and acid-base reaction are presented below. CO2 + H2O ⇌ H2CO3 H2CO3 ⇌ HCO3- + H+ Increasing the concentration of the carbonic anhydrase would __________ the rate constant of the forward reaction. a) decrease b) not affect c) increase

b) the concentration of the enzyme is independent of the rate constant because the enzyme can only catalyze the conversion of reactants to products at a specific rate. Increasing the concentration of the enzyme, however, would increase the absolute number of reactions occurring simultaneously; thus, the rate of reaction (but not the rate constant) would increase

Normal neurodevelopment in children is typically characterized by the acquisition of personal, social, academic, and occupational functioning. These functions are often learned and developed before the child begins primary education. During this period, the child learns social skills and how to control executive functions. Neurodevelopmental disorders involve developmental deficits that are manifested as impairments in normal neurodevelopment. Impairments in intelligence and social skills are often associated with neurodevelopmental disorders, and they frequently occur together. A child and adolescent psychiatrist wanted to further characterize children with neurodevelopmental disorders according to several protocols. The psychiatrist observed all children with any identified impairments of social skills and any associated intellectual disability The psychiatrist noted the following: communication disorder, impairment in attention, impairment in organization, motor disorder, repetitive behaviors, restricted behaviors, or other interests. The child and adolescent psychiatrist concluded that children with repetitive and restricted interests or patterns of behavior often demonstrate impairments in social skills. Some of the children who had restricted interests, repetitive patterns of behavior, and impairments in social skills also had intellectual impairments, language impairments, associated medical conditions, or other associated mental or behavioral disorders. It was found that specifying the individual characteristics of the neurodevelopmental disorders provided the child and adolescent psychiatrist the ability to better describe the diagnosis and associated symptoms to patients and their families. If a 5-year-old boy who, in comparison to the boy's matched agemates, has severe difficulties in learning skills involving reading, writing, and arithmetic and is without ongoing support, then the child will most likely exhibit which of the following? a) Be mature in social interactions b) Require supervision at all times c) Be able to care for personal needs d) Show much more complex spoken language than that of peers e) Need no support

b) the level of severity of intellectual disability is based on adaptive functioning (e.g. personal independence), and adaptive functioning determines the amount of support needed. In the absence of ongoing support, the adaptive deficits in children with severe intellectual disability will limit independence for all activities of daily living ("require supervision at all times"). "need no support" is wrong since all patients with intellectual disability, dependent on adaptive functioning, require some level of support. "be able to care for personal needs" can be eliminated since patients with severe intellectual disability require support for all activities of daily living

Consider the following reaction. P4(s)+5O2(g)+6H2O(l)→4H3PO4(aq) What is the oxidizing reagent in the reaction? a) O b) O2 c) P4 d) H2O

b) the oxidizing agent is the reactant, not the atom, that is responsible for receiving electrons from another atom in order to oxidize it. The oxygen gas goes from having an oxidation number of 0 to -2. This means that oxygen gas is reduced, but because it oxidized another atom by taking its electrons, we call it the oxidizing reagent. Reactant oxygen is elemental, and has oxidation number 0. product oxygen is in H20, with net charge of 0. total charge = 2(H) + (O) = 0 2(+1) + (O) = 2 + (O) = 0 O = -2 decrease in oxidation number indicates reduction and also identifies the oxidizing agent

Chromatography involves the separation of a mixture by allowing a mobile phase to travel along a stationary phase. In thin layer chromatography (TLC), a liquid solution is able to travel along a stationary plate. The distance that a particular compound travels compared to another compound can be determined by comparing the Rf factors for each compound. The Rf factor is determined by dividing the compound's distance by the total distance of the solvent. Which of the following compounds would have the smallest Rf factor in a standard thin-layer chromatography (TLC) experiment? a) Propane b) Glucose c) Butanol d) Hexane

b) the stationary phase in chromatography is typically attracted to the more polar compounds in a solution, while the mobile phase carried the nonpolar compounds. as a result, more polar compounds will move a shorter distance, resulting in a lower Rf factor. Glucose is a very polar molecule and would move a shorter distance compared to the other options

Which of the following best describes viruses? a) Obligate extracellular parasites b) Obligate intracellular parasites c) Facultative extracellular parasites d) Facultative intracellular parasites

b) Viruses require a host cell in order to complete their life cycle - hence, they are intracellular parasites. Because they are unable to replicate, hence "live" outside of their host, they are considered obligate intracellular parasites rather than facultative intracellular parasites

Carboxylic acids are found in soaps, oils, preservatives, skin care products, clothing, and amino acids. They often have unpleasant odors. Acetic acid is the main ingredient in vinegar. Propionic acid gives Swiss cheese its pungent smell. Butyric acid is in both rancid butter and body odor. Which of the following carboxylic acids is the most acidic? A. CH3CHClCH2COOH B. CH3CH2CCl2COOH C. CH3CH2CHClCOOH D. CH3CH2CH2COOH E. A and C are of most and equal acidity

b) the underlying factor here is the presence of highly electronegative functional groups. Their electron withdrawing capabilities stabilize the subsequent carboxylate anion, pushing equilibrium toward proton dissociation. This increases with the number of electronegative groups on the molecule, also being impacted by their distance from the acid functionality. Therefore, the answer choice with the most electronegative groups (which also happen to be in the closest proximity to the functional group) is clearly the most acidic.

In addition to deficits in social skills, excessive restricted, repetitive behaviors are also seen in autism spectrum disorder. Which of the following best describes a pattern of behavior that would most likely not be seen? a) Lining up toys b) Use of "you" only when not referring to self c) Spending hours writing out division tables d) Finger flicking e) Pacing a perimeter

b) the use of "you" when referring to self includes repetitive speech that may be seen in autism spectrum disorder. This repetitive speech (i.e. echolalia) may be delayed or immediate following words heard. Therefore, patients with autism spectrum disorder with symptoms of repetitive speech may use "you" when referreing to self and "use of 'you' only when not referring to self" would be the pattern of behavior least likely seen in autism spectrum disorder of the available choices and is the correct choice. In addition to repetitive speech that may be seen in autism spectrum disorder, other restricted, repetitive behaviors include patterns of nonverbal behavior ("pacing a perimeter" is wrong), abnormal intense focus ("spending hours writing out division tables" is wrong), repetitive use of object ("lining up toys" is wrong), as well as simple motor stereotypes ("finger flicking" is wrong).

A box of mass 10kg is hung from the ceiling by a rope. Find the tension in the rope. a) 49N b) 98N c) 25N d) 10N

b) there are only two forces acting on the box: the force of gravity and the force of tension in the rope. Since the box is not in motion, we can assume that the system is in equilibrium and the net force is equal to zero. Fnet = Fg + FT = 0N rearranging, we can see that gravity and the force of tension will be equal and opposite Fg = -FT calculate the force of gravity using Newton's second law Fg = mg Fg = (10kg)(-9.8m/s^2) = -98N Note that the force of gravity is negative, since it acts in the downward direction. Use this value to solve for the force of tension. -FT = Fg = -98N FT = 98N

A mass hanging in equilibrium is attached to a fixed surface on the ceiling by a spring. The mass is pulled down from the ceiling, then released and allowed to move in simple harmonic motion. The mass does not lose energy due to friction or air resistance. Which of the following would increase the frequency with which the mass moves through the equilibrium position? a) Increase displacement of the pull downward b) Increase stiffness of the spring c) Decrease displacement of the pull downward d) Increase the mass

b) this problem focuses on understanding simple harmonic motion. The formula to identify the frequency, or cycles per second, that the mass moves is given below, where k is the spring constant of the spring and m is the mass of the object attached f = 1/2(pi)(squareroot k/m) notice that the frequency does not depend on how far the mass is displaced originally. If the mass is displaced more, it will simply be moving faster when it goes through the equilibrium position. It will not, however, move through the equilibrium position any more frequently than it would if it had bee displaced less. Increasing the mass of the object attached would increase the denominator in the formula, and would therefore decrease the frequency of the harmonic motion. Increasing the spring constant, k, would increase the numerator of the formula, which would result in an increase in the frequency of the motion. The spring constant is directly proportional to the stiffness of the spring; thus, increasing stiffness will increase frequency

Which of the following contains the greatest number of moles? a) 3g of Li b) 2g of H c) 5g of Cl d) 10g of Ag e) 20g of Au

b) to convert to moles, divide each choice by the atomic mass of the element

How do chylomicrons and VLDLs differ? a) Chylomicrons contain apoproteins, VLDLs do not. b) Chylomicrons are synthesized in the intestine, VLDLs are synthesized in the liver. c) Chylomicrons transport triacylglycerol, VLDLs transport cholesterol. d) VLDLs are another term for chylomicron remnants; they differ in age.

b) Chylomicrons and VLDLs are very similar. Both contain apolipoproteins and primarily transport triacylglycerol, eliminating choices (A) and (C). The only major difference between them is the tissue of origin. Chylomicrons transport dietary triacylglycerol and originate in the small intestine, while VLDLs transport newly synthesized triacylglycerol and originate in the liver.

Blood pressure is a function of cardiac output (heart rate x stroke volume), as well as peripheral resistance (a measure of friction between the blood and the blood vessel walls). Factors that can increase peripheral resistance include: A. vasoconstriction and low blood viscosity. B. vasoconstriction and high blood viscosity. C. vasodilation and low blood viscosity. D. vasodilation and high blood viscosity.

b) If peripheral resistance reflects friction between the blood and the walls of the blood vessels, both narrower blood vessels (vasoconstriction) and a thicker, more viscous blood will increase peripheral resistance.

In proton NMR spectroscopy, which compounds or functional groups show a characteristic peak in the range 9-10 ppm? A. halogenated alkanes B. aldehydes C. alcohols D. aromatic compounds

b) Nuclear magnetic resonance (NMR) is concerned with the magnetic properties of certain nuclei. Anything that removes electron density from around a nucleus deshields it and shifts the absorption to higher frequency. The more electronegative the atoms that are attached to the nucleus, the higher the absorption frequency. Thus, NMR is able to provide information on the types of functional groups present as each has a characteristic chemical shift range. Aldehydes have a very characteristic shift of 9-10 ppm.

If an atom is shifted from an energy state of n=1 to n=3. If the energy state drops back from n=3 to n=1 at once, which of the following is most likely to be emitted? a) electron b) photon c) positron d) neutron

b) The energy states referred to in this question are those of electrons. When electrons get excited and then return to their resting energy state, they give off electromagnetic radiation in the form of photons. Depending on the specific energy change, the photon emitted will be in the X-ray wavelength, visible wavelength, infrared, etc.

An environmental toxin has been found to directly disrupt normal gamete production in women. What tissue or organ is the toxin likely localizing to? a) Endometrium b) Ovaries c) Oviduct d) None of these e) Uterus

b) the most likely localization of the toxin would be to the ovaries, since this is where gamete production begins for females. For males, gametes are produced in the testes. The incorrect answers are all parts of the female reproductive system. The oviduct is where fertilization takes place. The endometrium (the lining of the uterus) is where the embryo will eventually implant

Phosphorus had 3 allotropes: red, white, and black. White is most reactive due in large part to having 60 degree bonds in a tetrahedral formation. Which of the following best explains the reason for the bond angle increasing reactivity? a) 60 degree angles are energetically favorable, making the allotrope less stable and thus more reactive. b) 60 degree angles are energetically unfavorable, making the allotrope less stable and thus more reactive. c) 60 degree angles are energetically favorable, making the allotrope more stable and thus more reactive. d) 60 degree angles are energetically unfavorable, making the allotrope more stable and thus more reactive.

b) 60 degree angles are disfavored based on VESPR and cause strain on the atoms. Hence they are less stable and more reactive.

What is the most correct definition of competitive inhibition? A. Another enzyme completes the same reaction and uses the available reactant B. An inhibitor binds directly to the active site and prevents the reactant from binding C. A metal cofactor prevents the binding of the reactant by binding at the active site D. An inhibitor binds to the enzyme at a binding site, and prevents the enzyme from catalyzing the reaction

b) Metal cofactors and ATP are often used to help boost enzyme activity, and are not competitive inhibitors. Non-competitive inhibition(D) occurs when an inhibitor is able to prevent the enzyme from binding with the reactant by binding to the enzyme at a site away from the active site, and change the enzyme's conformation so it cannot bind to the reactant. Competitive inhibition occurs when the inhibitor competes directly with the reactant at the active site, and this substrate takes the place of the reactant and prevents the reaction from occurring.

A 1kg ninja star is hung from the end of a vertical spring with a spring constant of 20 N/m. When the ninja star comes to rest, how far will the spring have stretched? A. 0.05 B. 0.5 C. 2.0 D. 2.5

b) Once the ninja star comes to rest at the end of the spring, the upward force by the spring must balance the downward force of gravity. That is, kx = mg. Solving for x yields x = mg/k (1)(10)/(20) = 0.5 m.

ompared to a methyl group, a trifluoromethyl group would be expected to: a) be smaller in size. b) increase the strength of an acid on the alpha carbon. c) have less steric hindrance. d) donate electron density to the alpha carbon.

b) Since fluorine is far more electronegative than hydrogen, it will pull electron density towards itself. This has the impact of stabilizing acids (explaining, for example, why trichloroacetic acid is far stronger than acetic acid). This makes (B) the correct answer. Fluorine is larger than hydrogen meaning it will both be larger and have more steric hindrance.

In a concentration electrochemical cell, two half-reactions contain the same electrode composition and ion content. The only difference is in the concentration of the ion solutions. This drives electron flow as the concentrations of the solutions reach equilibrium. In such a setup, which of the following is true? a) Electrons flow from the solution with higher concentration to the solution with the lower concentration b) Electrons flow from the cathode to the anode c) Electrons flow from the anode to the cathode d) Copper ions flow from the higher-concentration solution to the lower-concentration solution.

c)

Moving 2.5 x 10-6 coulomb of charge from point A to point B in an electric field requires 6.3 x 10-4 joule of work. The potential difference between points A and B is approximately a) 1.6 x 10^9 V b) 4.0 x 10^3 V c) 2.5 x 10^2 V d) 1.0 x 10^14 V

c)

Objects A and B move apart from one another. Each object is moving at 10 m/s in the direction opposite to the motion of the other object. Object A of the objects emits a tone of 1000 Hz. What is the frequency of the tone when heard by object B? Assume the speed of sound is 350 m/s a) Greater than 1100 Hz b) Between 1000 and 1100 Hz c) Between 900 and 1000 Hz d) Less than 900 Hz

c)

Reactant X can become product Y through various mechanisms. A one-step mechanism takes places with enthalpy change of A. A two step mechanism can take place where the individual reactions have enthalpies B and C, respectively. Which of the following represents the change in enthalpy from X to Y? a) A+B+C b) B+C-A c) B+C d) A-B-C

c)

Sound loss as it travels through a medium is referred to as: a) harmonic loss b) resonance c) attenuation d) the doppler effect

c)

The Haber process is a common mechanism for creating ammonia from nitrogen and hydrogen gas. The reaction is as follows: N2(g) + 3H2(g) → 2NH3(g) + heat. There is a large closed vat in which the Haber process occurs. Predict what would happen if the vat were to mechanically and instantly decrease in size, all else remaining constant. a) The amount of nitrogen gas in the vat would increase. b) There would be a significant decrease in temperature. c) There would be an increase the amount of ammonia. d) Temperature would remain constant.

c)

The Nernst equation: a) cannot typically be used to determine potentials of concentration cells. b) is independent of the number of electrons transferred in the cell reaction. c) relates electric potential to chemical concentrations. d) only provides electric potentials of galvanic cells at room temperature.

c)

Two metal plates are placed in close proximity and are connected in a circuit with a battery. The capacitance of the plates is C. If area of the plates triples and the distance between them quadruples, what is the capacitance? a) 9/4 C b) 9/16 C c) 3/4 C d) 3/16 C

c)

What is the energy of an electromagnetic wave with energy E if the wavelength is changed from 800 nm to 400 nm? a) E/2 b) E c) 2E d) E2

c)

Which of the following has a negative standard free energy change at 25 °C? I. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) II. 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g) III. 2H2O(l) → 2H2(g) + O2(g) a) I only b) II only c) I and II only d) II and III only

c)

Which of the following is FALSE regarding nonvolatile solutions? a) Nonvolatile solutions contain a solute with zero vapor pressure. b) An example of a nonvolatile solution is a solution of salt in water. c) Upon adding a nonvolatile solute to a liquid, the nonvolatile solution at the surface increases vapor pressure. d) For a solution containing a nonvolatile solute, the vapor pressure is equal to the vapor pressure of the pure solvent multiplied by its mole fraction.

c)

Which of the following is a transverse wave? a) A shock wave through the air. b) A sound wave. c) A vibrating string on a musical instrument. d) Pressure wave through a liquid

c)

Which of the following is capable of producing a real image? I. concave lens II. concave mirror III. convex lens IV. convex mirror a) I and IV only b) II and IV only c) II and III only d) I, II, III, and IV

c)

Which of the following is the approximate wavelength of a 30 Hz wave with a velocity of 50 m/s? a) 0.6 m b) 1.5 m c) 1.7 m d) 1500 m

c)

Which of the following is the correct order of the menstrual cycle? a) Menstruation, Secretory phase, proliferative phase, ovulation b) Ovulation, secretory phase, proliferative phase, menstruation c) Menstruation, proliferative phase, ovulation, secretory phase d) Ovulation, menstruation, secretory phase, proliferative phase

c)

Which of the following is the correct units for power as it relates to lenses? a) m b) focal length/wavelength c) m^-1 d) nm^2

c)

Which of the following statements regarding fetal circulation is FALSE? a) In the umbilical cord, there are more arteries than veins. b) The foramen ovale is the only shunt that connects two chambers of the heart. c) Blood flow in the ductus arteriosus is from the aorta to the pulmonary artery. d) The ductus venosus is the only shunt that bypasses the liver.

c)

Which of the following ways would not increase the solubility of a gas in a liquid? a) Increase pressure of the system b) Decrease temperature of the system c) Increase temperature of the system d) Decrease volume of the system

c)

Who has the most power? I.) An Olympic cyclist, weighing 100 kg, bicycling 200 meters in 10 seconds. II.) An Olympic weightlifter, lifting a mass of a 200 kg a height of 4 meters in 4 seconds. III.) A laptop, having a resistance of 4 ohms, using 20 volts. A.) II B.) III C.) I and II D.) I, II, and III

c)

You are given three capacitors, each of capacitance 5 farads. Which of the following capacitances could not be derived through placing the capacitors in any permutation of in parallel or in series in a circuit. Assume a constant voltage. a) 15 F b) 7.5 F c) 3.5 F d) 1.7 F

c)

Which of the following molecules are Lewis acids? (Me = methyl) A. BF3 and H2O B. NH3 and Me3C+ C. BF3 and Me3C+ D. NH3 and H2O

c) A Lewis acid is an electron pair acceptor by virtue of it having an empty orbital. Both BH3 and CH3C+ are electron deficient, and therefore are Lewis acids. {Mnemonic: lEwis Acid = Electron Acceptor}

Which of the following should be observed with the addition of a catalyst to a chemical reaction? A. the formation of a new product B. the consumption of the catalyst C. the activation energy is lowered D. the decrease in enthalpy

c) A catalyst speeds up a chemical reaction by lowering the activation energy of a reaction. The catalyst is never consumed, nor does it alter the reactants or products. The total enthalpy of the reaction is also not changed from what it would have been without the catalyst. Only the rate at which the reaction occurs and the activation energy is affected. The only answer option that is correct is [C].

A hamster is trained to press a lever in order to obtain food. This is done so under a fixed-interval schedule. What behavior would you expect him to exhibit? A. Repeatedly pressing the lever whenever hungry B. Pressing the lever only once, then waiting patiently for the food pellet before pressing it again C. Pressing the lever slowly at first, but more urgently as the end of the interval approaches D. Pressing the lever repeatedly, regardless of how hungry E. None of the above, as fixed-interval schedules fail to form strong associations

c) A fixed interval rewards the desired behavior the first time it is demonstrated after the fixed interval has passed. For that reason, both fixed interval and fixed ratio schedules show this phenomenon: there is virtually no response initially, immediately after the reward is given, but the behavior increases dramatically as the rat knows it is getting close to receiving the reward again, once the fixed interval has been eclipsed. Ultimately, C is correct.

The 1H NMR of a compound yields two distinct peaks: one doublet and one quartet. It molecular formula is found to be C4H8. After a reaction, the 1H NMR of the product yields one singlet peak. The product still contains 4 carbon atoms. Which of the following types of reactions occurred? a) hydration b) halogenation with HCl c) dehydrogenation d) nucleophilic substitutio

c) A hydration reation would return a hydrogen atom to the alkyl chain and would result in 5 distinct peaks being detected, not one. Halogenation would also return a hydrogen atom and would and would result in 4 distinct peaks. Nucleophilic substitution would not happen with an alkene like the one presented, but in general the substitution reaction should not affect the number or multiplicity of the peaks unless the nucleophile or the leaving group themselves had hydrogen atoms. The answer is (C) because only a dehydrogenation reaction would convert the product into a compound with a single peak. A clue is the fact that there is a reduction in the number of peaks and their multiplicity, suggesting that there is a decrease in the number of hydrogen atoms which would be indicative of a dehydrogenation reaction.

When I hear the word doping, I immediately think of the olympics. Athens 2004 was the most doped Olympics in history, with 29 reported infractions. Not surprisingly, weightlifting is the most doped sport, coming in with 36 violations historically and accounting for about 30% of all doping cases historically. As far as the most scandalous countries, Austria is first with 10 doping violations, followed by Greece and Russia (9 violations), and lastly the good old US of A with 8 violations. Which of the following is not true of steroid hormones? A. They are produced primarily by the gonads and adrenal cortex B. They can cross the membrane C. No conformational change takes place upon binding their receptor D. Their effects are slower, but longer-lived than peptide hormones E. They are not water soluble

c) A is true. Since they are derived from cholesterol, a non-polar molecule, it would make sense that they can cross the membrane. As evidence of this, their receptors are usually intracellular. B is true as well. C is false, and therefore the correct answer. They do undergo a conformational change when they bind their receptor. This then allows the molecule to bind directly to DNA, increasing or decreasing transcription of certain genes. D is true, which makes sense if you think about them altering the amount of mRNA and protein present in a cell (this would take longer to enact and have a longer-lasting effect). E is true. Since they are not water soluble, they must be carried by proteins in the bloodstream all around the body.

Which of the following has a negative standard free energy change at 25 C? I. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) II. 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g) III. 2H2O(l) → 2H2(g) + O2(g) a) I only b) II only c) I and II only c) II and III only

c) A negative standard free energy implies that a reaction proceeds spontaneously at 25C. CH4, methane, burns readily in oxygen when ignited, and sodium placed in water reacts violently to produce hydrogen gas and sodium hydroxide. Hydrogen burns readily in oxygen as well, meaning that the reverse reaction shown above is not spontaneous.

Which of the following reactions utilizes a reducing agent? a) Conversion of an alcohol to an ether b) Conversion of an alcohol to an ester c) Conversion of an alcohol to a hydrocarbon d) Conversion of an alcohol to a carboxylic acid

c) A reducing agent would result in a reduction of the reagent, thus a reduction in an alcohol. Reduction involves a decrease in the number of bonds to oxygen, thus the only option that fits this pattern is option (C), a hydrocarbon. Thus (C) is the correct answer.

The posterior pituitary contains the nerve terminals of neurons with their cell bodies in the hypothalamus. The pituitary itself receives and stores two hormones: ADH and oxytocin. Which of the following correctly orders events? A. CN VII and IX detect decreased blood volume, ADH secretion is increased, and water reabsorption takes place in the renal collecting ducts B. CN IX and X detect decreased blood volume, ADH secretion is increased, and water reabsorption is decreased in the renal collecting ducts C. Osmoreceptors detect increased osmolarity of the blood, ADH secretion is increased, and water reabsorption is increased in the renal collecting ducts D. Osmoreceptors detect decreased osmolarity of the blood, ADH secretion is decreased, and water reabsorption is decreased in the renal collecting ducts E. None of the above

c) ADH is secreted in response to two things: low blood volume or increased blood osmolarity (as sensed by baroreceptors and osmoreceptors, respectively, with the baroreceptors corresponding to cranial nerves IX and X). It then acts at the level of the renal collecting duct, increasing the permeability of the duct to water. Ultimately, water is reabsorbed from the filtrate in the nephron, in turn increasing both blood volume and pressure. Only C correlates with this.

How many discrete 1H-NMR signals would be expected to be seen in 2-propanol? a) 1 b) 2 c) 3 d) 4

c) Discrete 1H-NMR peaks will show up for each set of asymmetrical protons; any symmetrical hydrogen atoms will be consolidated into a single peak. Looking at 2-propanol, it has 2 -CH3 groups which are symmetrical and therefore will show up as one peak. It has one -OH will will show up as another peak, and it has a -CH (the C2) which will show up as the third discrete peak. This makes (C) the correct answer.

Which of the following are true regarding ideal gas assumptions? I. Gas molecules have no volume. II. Pressure is caused by collisions against the walls of the container. III. All collisions between molecules are elastic. A. I only B. I and II only C. I and III only D. I, II, and III

c) According to ideal gas assumptions, all gas molecules are very far away from other gas molecules and their volumes are negligible. Should two gas molecules collide, their collision will be elastic, meaning no kinetic energy is lost (the average kinetic energy can only be changed by heating/cooling the gas). While it is true pressure is caused by the collision of gas molecules against the walls of the container, this is not an assumption for an ideal gas, but rather a general fact of nature. We typically want our ideal gases at low pressures too.

Which of the following is the conjugate base for ammonia? a) NH3 b) NH4+ c) NH2- d) NH

c) Ammonia, NH3, can act as acid and donate a proton to become NH2-, which is its conjugate base. Thus (C) is the correct answer.

Which of the following ways would not increase the solubility of a gas in a liquid? a) increase pressure of the system b) Decrease temperature of the system c) Increase temperature of the system d) Decrease volume of the system

c) An easy example to remember for this type of problem is a simple Coke can. Just think about what will keep the carbonation the longest. It is clear that initially, when the can is very pressurized and you haven't opened it yet, the gas is very soluble in the coke. Similarly, we chill already opened coke to keep the carbonation longer. Decreasing the volume will give the gas molecules less room to move about and will thus also become more soluble. Thus the only one that does not fit is increasing the temperature of the system, which is somewhat obvious because if you increase the temperature, the gas molecules would move much faster, making solubility difficult.

Increases in which of the following hormones causes sleepiness? a) Cortisol b) Growth hormone c) Melatonin d) Oxytocin

c) As light diminishes throughout the day, the pineal gland increases secretion of melatonin, resulting in sleepiness. Cortisol levels, choice (A), increase throughout the early morning, resulting in wakefulness. Growth hormone secretion, choice (B), peaks during slow-wave sleep. Oxytocin, choice (D), is associated with uterine contractions in childbirth, milk letdown, and bonding behavior.

Arrange the events below in the proper sequence from beginning to end of neurotransmission. 1) Neurotransmitter vesicles fuse with the membrane 2) Neurotransmitter vesicles are released within the pre-synaptic cell 3) Neurotransmitter is released into the synaptic cleft 4) Voltage gated calcium channels are activated 5) Neurotransmitter binds to receptors on the dendrite of the post-synaptic cell a) 2-1-4-3-5 b) 1-2-3-4-5 c) 4-2-1-3-5 d) 2-1-3-5-4

c) As the flow of charge moves down the pre-synaptic neuron's axon, the charge imbalance activates voltage gated calcium channels near the end of the axon (4). This opening of the channels causes a rush of calcium into the cell, which activates the release of vesicles containing neurotransmitter within the pre-synaptic cell (2). These vesicles can then fuse with the membrane of the pre-synaptic cell (1), causing a release of neurotransmitter into the synaptic cleft (3). The neurotransmitter then flows across the synaptic cleft where it binds to receptors on the post-synaptic cell (5) and the message can then be propagated along that cell.

The addition of an acid and heat to 2-oxocyclopentanecarboxylic acid yields a: A. cyclopentene B. cyclopentanol C. cyclopentanone D. cyclopentanecarboxylic acid

c) Beta-keto carboxylic acids undergo decarboxylation through ring formations. The carbonyl bond of the ketone will react with the alcohol group of the carboxylic acid to form a ring and release the carboxylic acid as CO2. The remaining enol will tautomerize into a carbonyl group again, leaving cyclopentanone.

It is well known that methylation of cytosine residues within CpG dinucleotides represents an important mechanism of gene expression control. Regulation of DNA methylation is crucial in many processes such as differentiation, growth and development. Hypermethylation of the gene promoter causes transcriptional silencing. Aberrant methylation may contribute to the development of a broad range of malignant tumors. Based on the foregoing, which group of genes is prone to methylation in a cancer cell? A. genes that stimulate angiogenesis B. genes that stimulate cell growth C. genes responsible for the promotion of apoptosis D. oncogenes.

c) Cancerogenesis is an evolutionary process. Cancer cells are under heavy selective pressure and only those cells that possess appropriate genetic characteristics will survive. All changes that result in increased angiogenesis, cell growth and expression of oncogenes favor cancer development. On the other hand, apoptosis (programmed cell death) represents the way in which an organism eliminates potential cancer cells. Silencing the genes responsible for promotion of apoptosis is an essential step in malignant tumor development.

Mantis shrimp exhibit complex mating habits compared to many other crustaceans. Their bodies are quite colorful and their eyesight is superior to that of humans, particularly in their ability to detect ultraviolet and infrared light. Curiously, those species of mantis shrimp with the best eyesight are also those that are the most colorful. This fact suggests that a) mantis shrimp are monogamous b) mantis shrimp exhibit advanced feeding patterns compared to other crustaceans c) vision and coloration co-evolved as vision improved, seeing coloration, and coloration improved, being more attractive d) male mantis shrimp are more colorful than female mantis shrimp

c) Complexity does not necessitate monogamy, hence (A) is out. The question tells us nothing about the differences between males and females, so (D) is out. There is also nothing we can use to conclude anything about the feeding patterns, so (B) is out. (C) is reasonable because it follows logically from a statement that discusses speciation, coloration, and vision.

A 2kg object falls from a height of 3m onto a spring, which compresses 20cm. What is the spring constant? a) 573N/m b) 184N/m c) 3136N/m d) 2445N/m e) 5221N/m

c) Conservation of energy is the key here. Initial energy is all gravitational potential energy: Ei = mg(h+x) note that the final height change is equal to the height above the spring added to the displacement of the spring. This is equal to the final energy, which is all spring potential energy: Ef = 1/2kx^2 set these equations equal and solve for the spring constant 1/2kx^2 = mg(h+x) k = 2(2kg)(9.8m/s)(3m+.2m)/(.2m^2) k = 3136N/m

Acetic acid reacts more rapidly with methanol than with ethanol to form an ester. Most likely this is due to: A. an inductive electronic effect. B. a resonance effect. C. steric hindrance. D. an ortho effect.

c) Bulky groups on either the acid or alcohol slow the reaction due to steric hindrance.

A 10 meter steel rod at 10 degrees celsius is dangling from the edge of a building. It is 1 cm from the ground. If it is heated to 90 degrees celsius, will it touch the ground? (α=1.1 x 10-5 K-1) A. Yes, because it expands by 1.76 cm B. Yes, because it expands by 1.32 cm C. No, because it expands by 0.88 cm D. No, because it expands by 0.44 cm E. None of the above

c) First we need to find the change in length due to thermal expansion: ∆L=αL∆T ∆L=(1.1 x 10-5 K-1)(10 m)(90 degrees celsius - 10 degrees celsius) Note, the scales for kelvin and celsius are equivalent, thus no unit change is necessary. ∆L=0.0088m=0.88 cm Therefore, C is correct.

Let's say you are upset with a sister. You decide to place her new gold earrings in the fire. Assuming they weigh 400 g and begin at 20 degrees Celsius, how much heat would be required to entirely melt them? (The melting point of gold is 1064 degrees Celsius, its heat of fusion is 6.37 x 10^4 J/kg, and its specific heat is 126 J/kg x K.) A. 58 kJ B. 68 kJ C. 78 kJ D. 88 kJ E. None of the above

c) First, we need to figure out how much heat is necessary to raise the temperature of the gold earrings to the actual melting point of gold. This (the heat required to raise the gold earrings from 25 degrees Celsius to 1064 degrees Celsius is: q = mc∆T =(.4 kg)(126 J/kg x K)(1064 K - 20 K) =52.6 kJ This is the amount of heat to get the earrings to their melting point. Next, we need to figure out how much heat is needed to melt them. This looks like the following: q=mL q=(.4 kg)(6.37 x 10^4 kg) q=25.5 kJ So, overall, we need 52.6 kJ + 25.5 kJ = 78.1 kJ of heat to melt the gold earrings. Note, don't be afraid to approximate along the way. The MCAT will generally grant you this flexibility withs its answer choices.

Which of the following is least likely to cause denaturation of proteins? a) Heating the protein to 100 °C b) Adding 8 M urea c) Moving it to a more hypotonic environment d) Adding a detergent such as sodium dodecyl sulfate

c) High salt concentrations and detergents can denature a protein, as can high temperatures. But moving a protein to a hypotonic environment—that is, a lower solute concentration— should not lead to denaturation.

Which of the following is incorrect regarding female/male differences? a) Both males and females produce progesterone b) Males produce testosterone in higher amounts than estrogen c) Males only produce testosterone, but females produce estrogen both estrogen and testosterone d) Females produce estrogen in higher amounts than testosterone e) Both males and females produce testosterone and estrogen

c) Hormone balance is extremely important in both developing the male and female fetus. Hormone levels can regulate and determine the relative level of sex characteristics that we see in individuals. Both sexes produces testosterone and estrogen, but utilize the hormones in different ways. Testosterone is produced at higher levels in males and is used to develop male secondary sex characteristics. Estrogen is produced at higher levels in females and is used to develop female secondary sex characteristics. Progesterone is a secondary sex hormone that is also produced in both sexes. Females use progesterone to regulate the menstrual cycle, and levels of the hormone vary in women

Color-blindness is a common sex-linked recessive trait in humans. If a woman is color blind, which is the most accurate statement about color-blind individuals in her family line? A. Both of her parents were color blind. B. Both of her parents were carriers of color blindness. C. Both of her parents, at least one of her mother's parents, and at least one of her father's parents had the gene. D. Both of her parents, both of her mother's parents, and at least one of her father's parents had the gene.

c) If a woman is born color blind (a sex-linked recessive trait: XCXC), she must have a color blind father (XCY) who can donate one recessive X gene and a mother who was at least a carrier (XCXC, or XCX). The father must have received the color blindness allele from his mother. The mother must have had at least one parent with the color blindness allele.

A cruise missile is fired at an angle with the horizontal. The air resistance is negligible. The initial horizontal velocity component is twice that of the initial vertical velocity component. The trajectory of the cruise missile is best described as: A. Semicircular B. Translational C. Parabolic D. Hyperbolic

c) If air resistance is neglected, the trajectories of all projectiles fired near the surface of the earth follow a parabolic path because the horizontal velocity is constant while the vertical acceleration is also constant.

A cruise missile is fired at an angle with the horizontal. The air resistance is negligible. The initial horizontal velocity component is twice that of the initial vertical velocity component. The trajectory of the cruise missile is best described as: A. Semicircular B. Translational C. Parabolic D. Hyperbolic

c) If air resistance is neglected, the trajectories of all projectiles fired near the surface of the earth follow a parabolic path because the horizontal velocity is constant while the vertical acceleration is also constant.

A 13 gram sample of an unknown hydrocarbon is a gas at room temperature (25 °C) and atmospheric pressure. Its volume is 11.2 liters. Which of the following could the hydrocarbon be? Note: the ideal gas constant is 0.082 (L*atm)/(K*mol) a. CH b. C2H4 c. C2H2 d. C3H3

c) In this question, we use the ideal gas law, PV = nRT. First of all, we calculate the number of mols in the volume of 11.2 L. n = PV/RT, or n = (1*11.2)/(0.082*298). This gives us roughly n= 0.5 mol. You can bypass this by remembering that there are 22.4 L in a gaseous mol at STP. Thus, there is 0.5 mol of a substance that we know weighs 13g. The molar mass must be 26 g/mol then. With the knowledge that C = 12g/mol and H = 1g/mol (standard knowledge), we find that the hydrocarbon should be C2H2.

Each individual in a group of teenagers is asked to estimate the height of a tree. One individual estimates the height to be 25 feet, but after discussing with the group is convinced that the height is likely closer to 40 feet. Which type of conformity is seen here? a) Obedience b) Identification c) Internalization d) Compliance

c) Internalization refers to the type of conformity in which an individual changes her outward opinion to match the group and also personally agrees with those ideas.

Hydroquinone is a benzene ring with two hydroxyl groups, while hydroxyquinone contains two carbonyls and a variable number of hydroxyl groups. How many steps does it take to convert quinones into hydroxyquinones? A. 1 step of reduction B. 2 steps of reduction C. 1 step of oxidation D. 2 steps of oxidation E. No such reaction occurs

c) It is one step of oxidation that converts quinones to hydroxyquinones. Quinones are derived through the oxidation of phenols initially. Ultimately, C is correct.

A person stands on a scale in an elevator (true, it does not happen everyday but it is the sort of insanity that happens on the MCAT!). She notices that the scale is reading lower than her normal weight. Which of the following most reasonably describes the motion of the elevator? A. It is moving down and slowing down. B. It is moving down at constant speed. C. It is moving up and slowing down. D. It is moving up and speeding up.

c) Let's randomly assign the upwards direction as positive. If up is positive, keeping in mind that her weight is directed down (i.e. towards the center of the Earth), the scale pushes up so that she does not go through the scale, and we know that the sum of forces is equal to ma from Newton's 2nd Law, we get: Fscale - weight = ma Examine the preceding equation again keeping in mind the following interpretation: The scale reading is less than her normal weight, so ma and thus the acceleration must be negative; i.e., down. Downward acceleration means either: (1) something speeds up while moving down, or (2) something slows down while moving up (i.e. upward deceleration).

Split peaks in NMR suggest: a) the presence of a functional group (e.g., -OH) in a molecule. b) the presence of chemically equivalent adjacent carbon atoms. c) the presence of neighboring hydrogen atoms which are not chemically equivalent. d) the presence of neighboring hydrogen atoms which are chemically equivalent.

c) NMR, or nuclear magnetic resonance, is a technique used to determine the structure of molecules with respect to hydrogen atoms. Splitting of peaks in NMR suggests chemically non-equivalent, though adjacent, hydrogen atoms. Thus (C) is the correct answer.

The body's pH is tightly regulated because specific enzymes function best within a narrow pH range. What is the approximate pH of a 1.2 × 10-5 M aqueous solution of NaOH? a) 4.92 b) 7.5 c) 9.08 d) 12.45

c) NaOH is a strong base; as such, there will be 1.2 × 10-5 M OH- in solution. Based on this information alone, the pOH must be between 4 and 5, and the pH must be between 9 and 10. Using the shortcut, pOH ≈ 5 - 0.12 = 4.88. pH = 14 - pOH = 9.12 (actual = 9.08).

Osteocytes exchange nutrients through which structures in bone tissue? a) Lamellae b) Haversian canals c) Canaliculi d) Lacunae

c) Osteocytes are differentiated osteoblasts that have become imbedded in hydroxyapatite bone matrix. The osteocytes are found in small gaps in bone matrix called lacunae and exchange nutrients with the blood using small canals called canaliculi. Lamellae are the concentric regions of osteocutes that are arranged around the central Haversian canal. The canal houses blood vessels and nerves to nourish and stimulate the osteocytes via the canaliculi

Dr. Frankenstein notices that his creation has an unusual genetic disorder which results in a change in one amino acid residue on pepsin. This mutated pepsin has optimal activity at a pH of 4. What effect is expected on the creation? a) Neurons will decrease firing speed b) There will be a noticeable increase of oxygen in tissue c) Digestion will be severely suppressed d) No muscle contraction due to an absence in the release of Ca2+.

c) Pepsin is a protease, meaning it catalyzes the splitting of proteins. It is usually found in the stomach, which has a pH between 2-3. If pepsin is modified such that it has an optimal enzymatic activity at pH 4, the protease will not be as effective in the stomach, thus severely suppressing digestion.

Primary groups differ from secondary groups in that: a) groups are shorter-lived than secondary groups. b) primary groups are larger than secondary groups. c) primary groups are formed of stronger bonds than secondary groups. d) primary groups are assigned while secondary groups are chosen.

c) Primary groups have direct and close bonds between members, providing warm, personal, and intimate relationships to its members. Secondary groups, in contrast, form superficial bonds and tend to last for a shorter period of time.

Which of the following is true regarding eggs in the female reproductive system? a) Production of eggs begins at puberty. b) The mature ovum is formed while inside the ovary. c) The zona pellucida is the primary regulating structure for entry by sperm cells. d) Polar bodies are approximately equal in size to the oocytes.

c) Production of egg cells begins prior to birth, hence (A) is incorrect. (B) is incorrect because the secondary oocyte is released from the ovary and the mature ovum is formed after fertilization which occurs after ovulation (i.e. outside the ovary) either in the fallopian tube or in the uterus. (D) is incorrect because polar bodies are significantly smaller than the oocytes as a mechanism of conserving cytoplasm for the egg cell to maintain maximal size. (C) is the correct answer because the zona pellucida is the glycoprotein structure surrounding the oocyte which regulates the entry of the sperm cells.

Which of the following is NOT true regarding prokaryotes and eukaryotes? a) Both prokaryotes and eukaryotes are bound by plasma membranes b) Both prokaryotes and eukaryotes use DNA as their genetic material c) Both prokaryotes and eukaryotes contain membrane-bound organelles d) While eukaryotes contain membrane-bound organelles, prokaryotes do not

c) Prokaryotic cells (bacteria, archaea) are simpler than eukaryotic cells (protists, fungi, plants, animals). For example, prokaryotic cells lack a nucleus, as well as cellular organelles, as opposed to eukaryotic cells which have both of these.

Glucocorticoids have been implicated in stress-related weight gain because: a) they increase appetite and decrease satiety signals. b) they increase the activity of catabolic hormones. c) they increase glucose levels, which causes insulin secretion. d) they interfere with activity of the leptin receptor.

c) Short-term glucocorticoid exposure causes a release of glucose and the hydrolysis of fats from adipocytes. However, if this glucose is not used for metabolism, it causes an increase in glucose level which promotes fat storage. The net result is the release of glucose from the liver to be converted into lipids in the adipose tissue under insulin stimulation.

A new noble gas X is constructed in the laboratory. The gas is noted to be monatomic. Which of the following intermolecular forces should be present in the gas? a) Dipole-Dipole b) Hydrogen Bonding c) London Dispersion d) None of the above

c) Since the gas is a noble gas, we know that it is inert; thus it is very easy to make the mistake and say that the gas has no intermolecular forces. This is incorrect! London dispersion forces always exist between any two atoms because the electron densities around those atoms are in constant flux. Between any two gas particles of X, London dispersion forces would be noted, albeit to a small extent. The note that the gas is monatomic just means that each atom of the gas stands alone, and that the gas molecules do not exist in a form like X2, like chlorine and bromine gas exist. This is irrelevant to the question.

Which of the following pairs of molecules would be most easily separated by liquid chromatography with a nonpolar stationary phase and a polar mobile phase? a) D-alanine and L-alanine b) 2-propanol and 1-propanol c) free fatty acid and phospholipid d) D-glucose and L-glucose

c) Since the liquid chromatography procedure is separating based on polarity, we're looking for pairs of molecules that will have differing polarities. D- and L-alanine as well as D- and L-glucose are enantiomers and will have functionally identical polarities. 1- and 2-propanol are also very similar in polarity due to their size and equivalent number of hydroxyl groups. Phospholipids are far more polar than free fatty acids due to the highly hydrophilic head.

Intermediate filaments are not responsible for which of the following in eukaryotic cells? a) Providing structure and shape to the nucleus. b) Giving mechanical support for the cell. c) Setting the limit for cell size. d) Providing the cell a degree of extensibility.

c) Since the primary mode of transport of substances in a cell relies on diffusion, the size of a cell is predominantly limited by its surface area to volume ratio.

You are told that a chloride containing compound has a molecular mass of 78.5 g/mol. Its H-NMR shows two signals, one which is split into 7 peaks and the other into 2 peaks. What is the compound? a) 1-chloropropane b) 1-chlorobutene c) 2-chloropropane d) 2-chloropropene

c) Solving this problem may require some guesswork, but we can approach it in a systematic answer. We know that the 7 peaks on the H-NMR indicate that there are 6 equivalent neighbouring hydrogen for the hydrogen producing this signal. In order to have 6 equivalent hydrogen, the neighbouring hydrogen likely belong to two bordering methyl (-CH3) groups. The other signal, which has two peaks, must be generated by the methyl groups (which are equivalent). These two methyl groups share a common single hydrogen neighbour. We also know that the compound contains chloride. If the compound has only three carbons (deduced from the H-NMR reasoning above), the chloride must belong to the middle carbon, which gives us: CH3CH-Cl-CH3, which has a molecular weight of 75.5 g/mol.

In college, professors may often joke that if you study while drinking beer, then you need to take your exam while drinking beer. This is referred to as state-dependent recall. What else could cause a state-dependent recall effect? I. Being in a manic state II. Being in a depressed state III. Being in high elevation A. I B. II C. I and II D. I, II, and III E. None of the above

c) State-dependent recall only concerns itself with internal, not external, states of the individual. By this logic, both a manic state and depressed state would be internal, while elevation is obviously external. This makes C correct.

Which of the following appropriately approximates the infrared absorption of hydroxyl (-OH) groups in an organic molecule? a) 2100 cm-1 b) 2800 cm-1 c) 3100 cm-1 d) 3500 cm-1

c) The MCAT won't ask too many specific questions regarding IR spectra, however knowing that the -OH group appears at around 3100 cm-1 is expected knowledge. (C) is the correct answer.

How many signals would we expect in C13-NMR for benzoic acid (benzene with a carboxyl group attached)? a) 3 signals b) 4 signals c) 5 signals d) 6 signals

c) The answer is (C), 5 signals. The carbon from the carboxyl group would produce one signal. A benzene ring that is symmetrical (such as with a single substituted group) would produce four signals (single signals from carbon 1, carbons 2 and 6, carbons 3 and 4, and carbon 5).

Which of the following lab techniques use the concept of mass to charge ratio? a) Distillation b) Crystallization c) Mass Spectroscopy d) Nuclear Magnetic Resonance

c) The answer is (C), Mass Spectroscopy. Distillation and Crystallization are methods for sample purification. Distillation is based on the concept of differences in vapour pressure in order to separate two volatile liquids. Crystallization is based on the concept that pure substances form crystal structures more readily than impure substances. Nuclear Magnetic Resonance is a form of spectroscopy that measures the magnetic properties of molecular structures based on their atomic nuclei. In Mass Spectroscopy, compounds are ionized and then passed through a magnetic field, which projects the ionized compound along a curved path dependent on its mass and charge.

A student is volunteering in a hospital with a stroke center. When asked what he believes is the prevalence of stroke among those greater than 65 years old, the student states that it is probably about 40% even though data analysis indicates that it is significantly lower. What accounts for this error? a) Deductive reasoning b) Representativeness heuristic c) Base rate fallacy d) Confirmation bias

c) The base rate fallacy occurs when prototypical or stereotypical factors are used for analysis rather than actual data. Because the student is volunteering in a hospital with a stroke center, he sees more patients who have experienced a stroke than would be expected in a hospital without a stroke center. Thus, this experience changes his perception and results in base rate fallacy. Deductive reasoning, choice (A), refers to drawing conclusions by integrating different pieces of evidence. The representativeness heuristic, choice (B), involves categorization and classification based on how well an individual example fits its category. Confirmation bias, choice (D), occurs when a person only seeks information that reinforces his or her opinions.

An underlying concept in general chemistry, organic chemistry, and biochemistry is that the more stable a conjugate base, the more likely it is for a proton to leave. Stability is determined by periodic trends, size of the anion, and resonance structures. Carboxylic acids are very versatile. They can be reacted in one step to form all, but which of the following compounds? A. Esters B. Amides C. Alkenes D. Alcohols E. They can form all of the above in one step

c) The conversion to alkenes in one step cannot take place. Esters are formed via a nucleophilic acyl substitution reaction with alcohols. Amides are also formed by a nucleophilic acyl substitution reaction, however with ammonia. There are a variety of reducing agents to form alcohols in one step. To get alkenes, you first have to reduce to alcohols and then transform these into alkenes by elimination.

A construction worker uses a crane to vertically lift an object weighing 2000 N to the top of a platform at a constant rate. If it takes 30 seconds to lift the object 150 meters, what is the rate of energy consumed by the motor in the crane? A. 5.0 kW B. 8.0 kW C. 10.0 kW D. 12.0 kW

c) We can use the equation Power = Force*velocity to solve this problem. The object moves 150 meters in 30 seconds, so the velocity must be (150m/30s) = 5 m/s. Plugging this back into the original equation of P = Fv, then P = (2000 N)(5 m/s) = 10 kW.

A sealed vessel holds air and liquid water. Which of the following conditions would greatly increase the amount of air dissolved into the water? A. Increasing the size of the vessel B. Decreasing the temperature of the container C. Adding argon gas to the vessel D. Increasing the temperature of the container

c) The correct answer is C. Temperature change does increase the solvation ability of gas into liquid, but not significantly. However, we can easily recognize that a warm soda loses air much faster than a cold soda. Thus, it seems that answer B could be correct. However, in a sealed vessel, the factor that will increase the amount of air dissolved most immediately is the increase of pressure. The pressure is increased when another gas in forced in the system, like argon. The increase pressure will drive the equilibrium to force more air into the water.

The diaphysis refers to the: a) connective tissue connecting bone to tendon. b) connective tissue connecting bone to ligament. c) shaft of the bone. d) marrow of the bone.

c) The diaphysis is the region of bone which makes up the shaft, thus (C) is the correct answer

Glen brings cookies to work. Although you have not yet tasted them, you say to another coworker, "Glen is such a great guy; I'm sure these cookies are fantastic!" What type of bias is this? a) Reliance on central traits b) Direct benefits c) Halo effect d) Similarity

c) The halo effect is a cognitive bias in which judgments of an individual's character can be affected by the overall impression of the individual.

Phase changes have a variety of names. The phase change from liquid to solid is called freezing or solidification, while that from solid to liquid is termed melting or fusion. When going from liquid to gas, it is called boiling. Last, gas to liquid is called condensation. Which of the following is not true of the heat of transformation? A. It does not result in a temperature change B. It is related to changes in potential energy C. It is related to changes in kinetic energy D. It creates a greater number of microstates E. None of the above

c) The heat of transformation is the heat added to a substance during a phase change. A is true, phase changes do not result in a change in temperature. A temperature change does not occur until all of the substance has changed phases; no matter how much heat is added to a mass of ice at zero degrees celsius, the temperature will not rise until all of the ice has been turned into water. B is true as well. Phase changes are related to potential energy, not kinetic energy. The previous statement about no change in temperature should illustrate this nicely. Another way to think about it is low potential energy of ice given the relative closeness of the molecules to one another. Adding heat to this ice though allows them to move away from each other, breaking somewhat free of their hydrogen bonding. They now have greater freedom, permitting a greater number of microstates. This leads into D, which is also correct. Ultimately, C is the correct answer because it is a false statement, as explained.

For which of the following allele frequencies will about 80% of the population be homozygous recessive, assuming p is the dominant allele and q is the recessive allele? a) p=0.8, q=0.2 b) p=0.2, q=0.8 c) p=0.1, q=0.9 c) p=0.4, q=0.6

c) The homozygous recessive population is expressed by the term q2 = 0.9*0.9 = 0.81. This term reflects the percentage of the population with two q alleles, thus option (C) obtains a population where 80% are homozygous recessive.

A science lab studies enzyme kinetics for a particular set of enzymes and substrates. It is found that the enzyme's active site differs in conformation from the substrate however when the substrate moves in close proximity to the active site, small conformational changes take place to allow the substrate to bind. This evidence supports: a) the lock and key hypothesis. b) enzymatic reduction of activation energy. c) the induced-fit model. d) protease catalysis.

c) The model presented in the prompt is consistent with the induced-fit model, where the substrate causes conformational changes that allow for binding to the active site. Thus (C) is the correct answer.

Which of the following is the most accurate statement regarding the theory of Natural Selection? A. Individuals who reproduce in greater numbers are more likely to pass on their genes B. Individuals who have favorable random genetic mutations are not likely pass on their genes C. The environment can only support a finite number of individuals D. Individuals with the most genetic mutations are more likely pass on their genes

c) The most accurate statement is C. The statement for A can be true when discussing particular reproductive strategies, however, is not true in all cases. Individuals that are best adapted to their environment will have the greatest chance to pass on their genes, not the ones that produce the most amount of offspring. If an animal produces 1000 offspring and 999 of them die, then the fitness level of that animal is very low, compared to another animal with high fitness that only produces 2 offspring and both live to pass on their genes. Statement B would be correct if it were stated oppositely, since favorable genetic mutations is what creates natural selection. Statement D is not at all accurate regarding the principles of natural selection.

The nodes of ranvier are responsible for: a) increasing the number of sodium channels in an axon. b) increasing the speed of electric conduction down an axon. c) regenerating an action potential as it travels down the axon. d) stabilizing electric impulses within an axon.

c) The nodes of ranvier are open to the extracellular space (unlike the myelinated areas of the axon), thus ion exchange happens here and allows for regeneration of the action potential as it moves down the axon. Nodes of ranvier are NOT responsible for increased speed down the axon, however; it is the myelin sheath which allows for quick transmission of signal without significant loss of the action potential signal. Thus (C) is the correct answer.

An oil consisting of high molecular weight hydrocarbons is present in a sample of waste water. Which of the following solvents would be the best extraction solvent for the oil? a) methanol b) acetone c) hexane d) diethyl ether

c) The oil is nonpolar. Oil is most soluble in hexane since it is a nonpolar solvent (i.e. like dissolves like). Methanol and acetone can't be used since they are miscible with water (polar solvents). Diethyl ether is a semipolar solvent and would extract less oil than hexane.

Which represents a repeating structural unit of chromatin? a) Nucleus b) Nucleoid c) Nucleosome d) Nucleolus

c) the nucleosome is a structure integral to DNA packaging - consisting of segments of DNA wrapped around a histone core. The nucleus is the cell organelle involved that contains genetic material. In turn, the nucleolus is an organelle within the nucleus itself and functions in rRNA synthesis. A nucleoid is found in prokaryotic organisms and represents the area where genetic material is located.

In a small lake, sea urchins graze upon small grasses that grow on the bottom. After the introduction of an exotic sea urchin, the small grasses became over grazed and absent. To solve the problem, a species of otter is introduced into the lake to predate upon the sea urchins, and the balance between the urchins and sea grasses is restored. What would be the appropriate term for the otter that was introduced? A. tertiary consumer B. top carnivore C. keystone predator D. primary consumer

c) The otter would be considered a SECONDARY consumer, the urchins are the primary consumers, and a hypothetical predator of the otter would be a tertiary consumer. Since the otter is responsible for preventing overgrazing of the small grasses by predating on the out of control urchin population, it is termed a keystone predator that exerts a "top-down" effect on the ecosystem.

Lens power has a units of: a) m b) m-1/2 c) m-1 d) unitless

c) The power can be calculated as the inverse of focal length, thus the units are 1/m. Thus (C) is the correct answer.

Many pets will run toward the kitchen when they hear the sound of a can opener opening a can of pet food. The sound of the can opener is a: a) conditioned response. b) unconditioned response. c) conditioned stimulus. d) unconditioned stimulus.

c) The sound of a can opener would not normally produce a response on its own, making it a stimulus that must have been conditioned by association with the sound with food.

Which of the following interactions result in the specificity and tight binding of the two strands in the DNA double helix? a) London dispersion forces b) Covalent bonding c) Hydrogen bonding d) Dipole-dipole interactions

c) The two strands of a double helix stay together due to hydrogen bonding between the bases. The bases C and G form three hydrogen bonds together, and the bases T and A form two hydrogen bonds together. It is this hydrogen bonding that provides great specificity and stability to the DNA double helix.

What is the major intermolecular force in the following compound, given that the difference in boiling point between its two stereoisomers is less than 3%? CH3CH=CHCH2CH3 a) dipole-dipole b) hydrogen bonding c) London dispersion d) ionic

c) This compound is nonpolar across the molecule, and thus has mainly London dispersion forces. Although the Z isomer has minor dipoles associated with it, the minor difference in boiling point indicates that dipole-dipole interactions are very minor contributors.

A young adult male claims to have had sexual relationships mostly with other men, although he has been attracted to women at times. What would be his most likely score on the Kinsey scale? a) 0 b) 1 c) 5 d) 6

c) This man is describing his sexuality as mostly homosexual, although he has also had some heterosexual attractions. The Kinsey scale scores a 6, choice (D), as exclusively homo-sexual. A score of 3 would equate to bisexuality. Thus, this man would likely score a 4 or 5.

Why are triacylglycerols used in the human body for energy storage? a) They are highly hydrated, and therefore can store lots of energy. b) They always have short fatty acid chains, for easy access by metabolic enzymes. c) The carbon atoms of the fatty acid chains are highly reduced, and therefore yield more energy upon oxidation. d) Polysaccharides, which would actually be a better energy storage form, would dissolve in the body.

c) Triacylglycerols are highly hydrophobic and therefore not highly hydrated (which would add extra weight from the water of hydration, taking away from the energy density of these molecules), eliminating choice (A). The fatty acid chains produce twice as much energy as polysaccharides during oxidation because they are highly reduced. The fatty acid chains vary in length and saturation.

Tropic hormones are hormones which: a) do not act on endocrine glands. b) act directly on target cells. c) are typically secreted by the anterior pituitary. d) are typically secreted by the posterior pituitary.

c) Tropic hormones are hormones which act directly on other endocrine glands, which in turn release hormones that act on target cells. TSH and ACTH are both examples of such hormones. The anterior pituitary is mainly responsible for the release of tropic hormones, thus (C) is the correct answer.

There are so many benefits to breastfeeding, including the transfer of antibodies from mother to child. This confers immunity to the child early in life, while they are vulnerable, and before vaccines and time are able to develop their own immune system. What is unique about prolactin? A. Undersecretion is pathologic in males B. It decreases milk production C. Secretion decreased by dopamine D. It is responsible for runner's high E. It prevents glucose uptake in certain tissues and stimulates fatty acid breakdown

c) Undersecretion in males is not pathologic since prolactin stimulates milk production in the mammary glands. Therefore, undersecretion will lead to no milk production in males, which is normal and not pathologic. A is eliminated. As discussed here, prolactin increases milk production, eliminating B. The release of dopamine from the hypothalamus decreases its secretion. High levels of estrogen and progesterone allow for development of milk ducts in preparation for lactation, but it is not until after the expulsion of the placenta that these levels drop and remove their block on milk production. This makes C correct. D and E are facilitated by endorphins and growth hormone, respectively, thus eliminating D and E.

For the most part, biological pH is slightly basic. However, the stomach is very acidic, and its contents must be swiftly neutralized by basic bicarbonate ions upon entering the small intestine, which has a basic pH. How many liters of 2 M Ba(OH)2 are needed to titrate a 4 L solution of 6 M H3PO4? a) 1.33 L b) 12 L c) 18 L d) 56 L

c) Use the equivalence point equation: NaVa = NbVb Ba(OH)2 can dissociate to give two hydroxide ions, so its normality is 2 M × 2 = 4 N. H3PO4 can dissociate to give three hydronium ions, so its normality is 6 M × 3 = 18 N. Plugging into the equation, we get (18 N)(4 L) = (4 N)(Vb). Therefore, Vb is 18 L.

In a laboratory, a plate of neurons is constructed composed with half of the neurons having a threshold potential of -50 mV and the other half with a threshold potential of -30 mV. Both types of neurons have a resting potential of -70 mV. 50 mV of voltage are applied uniformly across these plated neurons. Which of the following would be expected? a) 0% of the neurons would fire b) 50% of the neurons would fire c) 100% of the neurons would fire d) the percentage of neurons that would fire cannot be determined

c) We are given that 50 mV are applied to the neurons, thus both types of neurons would rise above their required threshold potentials from the resting potentials. Thus it would be expected that 100% of the neurons would fire. Thus (C) is the correct answer.

In the human body, glycerol and three fatty acids can act together to form triacyl glycerol in a process known as esterification. The reverse of this process is known as __________. a) transesterification b) reverse esterification c) saponification d) decarboxylation

c) When an alcohol and carboxylic acid are reacted together they can form an ester, in a process known as esterification. This is what happes with glycerol and fatty acids to form triacyl glycerol. The reverse of this process is an organic chemistry reaction known as saponification, in which an ester and water are reacted to form carboxylic acids and alcohol

In order to successfully accommodate for changes in depth of field, lens of the eye must perform which of the following functions when re-focusing on a closer object? a) Tilt b) Flatten c) Thicken d) Rotate

c) When looking at objects that are close, the lens of the eye must "thicken" to accommodate changes in depth of field. This is accomplished by contraction of the ciliary muscle, which allows the suspensory ligament to stretch. The lack of tension then allows the lens to draw up into its thicker resting state. If the vision is shifted to a far object, then ciliary muscles will relax, which increases tension on the lens via the suspensory ligament and causes it to "flatten." the lens does not "tilt" or "rotate"

Which of the following is NOT a difference that would allow one to distinguish a prokaryotic and a eukaryotic cell? a) Ribosomal subunit weight b) Presence of a nucleus c) Presence of a membrane on the outside surface of the cell d) Presence of membrane-bound organelles

c) Which of the following is NOT a difference that would allow one to distinguish a prokaryotic and a eukaryotic cell? Ribosomal subunit weight Presence of a nucleus Presence of a membrane on the outside surface of the cell Presence of membrane-bound organelles

Which element has the greatest electron affinity? a) Magnesium b) Oxygen c) Fluorine d) Carbon

c) electron affinity increases from left to right across a period and from bottom to top within a group in the periodic table. Electron affinity and electronegativity are directly related. Fluorine is the most electronegative element, and also has a very very high electron affinity. Addition of an electron to fluorine completes its valence octet, providing stability

Which of the following changes to a pendulum will affect the angular velocity? a) Raising the height from which the mass is released b) Increasing the mass on the end of the string c) Decreasing the length of the string d) Lowering the height from which the mass is released

c) for a pendulum ,the angular velocity is given by the equation w = square root (g/L) where g is the acceleration due to gravity and L is the length of the pendulum. of the available answer choices, only changing the length of the string will effect the angular velocity. w does not depend on mass or the release point of the pendulum

An action potential travels down a neuronal axon. Which of the following is occurring during depolarization of the neuron? a) Sodium flows into of the cell down its electrical gradient, but against its chemical gradient b) Potassium flows into the neuron down its electrical and chemical gradients c) Sodium flows into the neuron down its electrical and chemical gradients d) Sodium flows out of the neuron down its electrical and chemical gradients

c) it is important to recognize that sodium is flowing into the neuron during depolarization. The area outside of the neuron is electrically positive relative to the area inside of the neuron, resulting in the negative resting membrane potential of the cell. This potential allows positively charged sodium ions to flow from a high concentration of positive charge, towards the negative charge in the cell interior. Because the sodium travels from a region of relatively positive charge to a region of relatively negative charge, it is flowing down its electrical gradient. due to action by the sodium-potassium pump, there is also a large concentration of sodium ions outside of the cell,, relative to the small sodium ion concentration inside the cell. This imbalance creates a chemical gradient across the axon membrane. The opening of the voltage-gated sodium channels during depolarization allows sodium to flow down chemical gradient from high ion concentration to low ion concentration

During the course of a day, approximately three liters of plasma are filtered out of the capillaries, but are not reabsorbed into the vessels. This means that the volume of fluid stays in the interstitial space around the capillaries. What does the body do with this large volume of fluid? a) It exits the body as sweat b) It stays in the interstitial space until the blood volume is decreased c) It is absorbed into the lymphatic system d) It is transported to the kidney to exit the body as urine

c) lymphatic fluid is formed by absorbing the excess plasma that has been filtered from the capillaries. This occurs because more plasma is filtered out of the capillaries than can be reabsorbed back into the capillaries. This leads to a net filtration of plasma into the interstitium. The role of the lymphatic system is to absorb this filtered plasma and return it to circulation via a duct into the right atrium. A failure to collect the extracellular fluids can lead to swelling of the extremities, known as edema. When the lymphatic vessels collect fluid they also carry it through the lymph nodes, which house large populations of lymphocytes. These lymphocytes screen the blood for foreign antigens and can launch an immune response if pathogens are found

In a current-carrying wire, which of the following expressions best relates charge, current, velocity and the length of the wire? Assume θ is 90o. a) L=Iq/ν b) L=qvI c) L=qν/I d) L=Iν/q

c) the force of a charge in a magnetic field is given by the equation F = qvBsinθ. q is the charge, v is the velocity, and B is the magnetic field strength additionally, the force o a current-carrying wire in a magnetic field is given by the equation F = ILBsinθ. I is the current, L is the length of the wire, and B is the magnetic field strength. Because we assume the angle to be 90 degrees, we can set the two force equations equal to each other and derive the equation qvB = ILB by manipulating the variables, we can generate the equation L = qv/I. None of the other answer choices can be derived from these equations

Blood types are designated A, B, AB, and O depending on the glycoprotein presented on the surface of the red blood cells. If a person has glycoproteins IA and i. What is the person's blood type? a) O b) B c) A d) AB

c) the glycoproteins, I^A, I^B, and i are responsible for the A, B, and O blood types in humans respectively I^A and I^B are dominant to i, meaning that blood types A and B are dominant to O. Additionally, I^A and I^B can be co-dominant giving the AB blood type. The person in the question has I^A and i glycoproteins, giving the patient the A blood type, as I^A is dominant to i. Genotypically they will carry alleles for both A and O blood type, but their phenotype will be only A

Which of the following is not an acidic environment? a) Stomach b) Vagina c) Small intestine d) Lysosome e) Phagosome

c) the small intestine is a basic environment. Secretions from the pancreas into the duodenum help to neutralize chyme transferred from the stomach, resulting in a slightly basic environment in the small intestine. The stomach is highly acidic which helps kill microbes and assists with digestion. The vagina is also acidic to prevent the growth of pathogens. Lysosomes and phagosomes are acidic vacuoles that break down foreign pathogens

Which of the following describes a Brønsted-Lowry acid? a) A substance that accepts an electron pair b) A substance that donates an electron pair c) A substance that donates a proton d) A substance that produces hydroxide ions in an aqueous solution

c) there are three definitions for an acid that are commonly used: an Arrhenius acid, a Bronsted-Lowry acid, and a Lewis acid. Arrhenius acids are any substances that create hydrogen ions in solution, and Lewis acids are any substance that accept an electron pair. A Bronsted-Lowry acid is defined as any substance that donates a proton

Your neighbor asks you to check his mail while he is out of town, and you agree. Later that day, he asks you to water his plants as well. What technique for compliance is he using in this scenario a) Lowball technique b) that's not all technique c) foot in the door technique d) door in the face technique

c) this is a prime example of the foot in the door technique. The neighbor first asks for a small favor, and after receiving commitment, asks for a larger favor

Unlike eukaryotes, prokaryotes have no membrane-bound organelles. How, then, are prokaryotes able to generate energy? a) Prokaryotes do not generate energy b) Prokaryotes produce energy via photosynthesis c) Prokaryotes generate proton gradients across their plasma membranes d) Prokaryotes have specialized mitochondria e) Prokaryotes generate sodium gradients across their nuclear membranes

c) this question has several components for understanding what it is asking, and what the answer is. the first clue is the use of the word "energy," which is often code for ATP in biology. In eukaryotes, ATP is generated in the mitochondria through a long multi-step process, in which a proton gradient is established to produce ATP from glucose metabolism in the presence of oxygen. Note that even autotrophs require mitochondria in conjunction with chloroplasts; photosynthesis does not negate the necessity of an ion gradient for ATP synthesis prokaryotes do not have mitochondria, but do generate ATP to carry out many biomolecular functions. Because there are no membrane-bound organelles, in order to complete bacterial metabolism prokaryotes must generate a proton gradient between the intra- and extra-cellular spaces, generally between the plasma membrane and the cell wall. This allows an electron transport chain to function along the cell membrane, using the proton gradient between the membrane and the bacterial wall to generate ATP

Which of the following statements about mitochondria could be used as support for the endosymbiotic theory? a) Mitochondria help regulate apoptosis, which is the controlled death of aged or injured cells b) Plant cells contain both mitochondria and chloroplasts c) Like prokaryotes, a mitochondrion has a single circular chromosome d) A proton gradient along the inner mitochondrial membrane powers the aerobic production of ATP e) Cells that are involved in movement, such as muscle cells and the flagella of sperm, tend to contain comparatively large numbers of mitochondria

c) though all of the answer choices are correct statements, only one provides support for the endoxymbiotic theory. This commonly supported theory proposes that mitochondria arose as single celled prokaryotes that were engulfed by larger cells. These cells developed a symbiotic relationship that eventually led to current eukaryotic cells. So, for a statement to support this theory, it must make a connection between mitochondria and the prokaryotes from which they arose - such as the fact that they have similar DNA structures

Which of the following is true regarding the nephron? The collecting duct is permeable to water and responsive to aldosterone a) The distal tubule absorbs Na+ and HCO−3 while secreting Ca2+, H+, and K+ b) Bowman's capsule is repsonsible for preventing all proteins from entering the filtrate c) The renal corpuscle is made up of the glomerulus and Bowman's capsule d) Aldosterone acts at the collecting duct to increase membrane permeability to Na+ and K+

c) together, owman's capsule and the glomerulus make up the renal corpuscle. Blooc flows through the glomerulus, where high hydrostatic pressures force plasma through the fenestrations of the glomerular endothelium into Bowman's capsule. The substance that ends up in the capsule is called the filtrate, which then moves to the proximal tubule. Proteins, glucose, and ions are secreted from the proximal tubule back into the blood. The collecting duct is impermeable to water and is not particularly sensitive to aldosterone. Instead, aldosterone, a steroid hormone produced by the adrenal cortex, acts primarily at the distal tubule to increase sodium reabsorption, potassium secretion, and ultimately water reabsorption to increase blood pressure. The distal tubule absorbs Na+ and Ca2+, not HCO3-

Pea plants have two independently assorted genes that code for seed shape (round or wrinkled) and seed color (yellow or green), respectively. A researcher crosses two pea plants and observes that all F1 offspring have the same phenotype: round shape and yellow seeds. He then performs a test cross with an F1 offspring and observes four different phenotypes in a 1:1:1:1 ratio. Based on this information the researcher concludes the genotypes of the parents. Which of the following is true regarding a recessive allele? a) In a heterozygous offspring both the dominant and recessive alleles are expressed, but dominant allele is expressed more frequently b) In a heterozygous offspring the dominant and the recessive alleles are on the same chromosome c) In a heterozygous offspring the dominant allele is expressed and the recessive allele is suppressed d) In a homozygous recessive offspring both recessive alleles are on the same chromosome

c) A Mendelian gene generally has two types of alleles: dominant and recessive. An individual always contains two sets of chromosomes (homologous chromosomes) that contain the gene. If both chromosomes contain a dominant allele, then the dominant trait is expressed. If both contain the recessive allele, then the recessive trait is expressed. If an individual carries both alleles (a heterozygous individual), then only the dominant trait is observed. This occurs because the recessive allele is silenced and is not expressed in the presence of a dominant allele. If the recessive allele is expressed in conjunction with the dominant allele, then it is called incomplete dominance. In normal heterozygous genes, however, the recessive allele is not expressed. Each chromosome carries only one copy of each gene, and cannot accommodate two alleles for a single trait

The genetic code of codons has been described as being a degenerate code. Degeneracy suggests: a) that there are explicit codons which code for the start and stop of a peptide sequence. b) that codons are universal among species, irrespective of kingdom. c) the presence of synonymous mutations. d) every codon can only code for a single amino acid

c) Degeneracy is a term that states that there is redundancy for codons in terms of coding for amino acids. For instance there are four different codons (CCU, CCC, CCA, and CCG) which code for proline. This suggests the presence of synonymous mutations, which are mutations where the codon changes however the exact same amino acid is coded for because the mutation results in a synonymous codon. Thus (C) is the correct answer.

Which of the following would be most likely to be stored in long-term memory? a) A list of nonsense words b) A list of the dates of birth of 15 randomly selected people c) A list of the names of musicians in an individual's favorite bands d) A list of the dates of battles in the Peloponnesian War

c) The self-reference effect indicates that information that is most meaningful to an individual is the most likely to be memorized. Choice (C) is the most personally relevant to the individual memorizing the list.

When going from left to right on the periodic table, it is generally expected that: a) ionization energy decreases, electron affinity decreases. b) ionization energy decreases, electron affinity increases c) ionization energy increases, electron affinity increases. d) ionization energy increases, electron affinity decreases.

c) As we go right on the periodic table, the effective nuclear charge increases which results in a tighter affinity for the outermost electrons. Thus ionization energy will increase going from left to right as it takes more energy to remove the outermost electron. Electron affinity refers to the amount of energy released with the addition of an electron, which is functionally the likelihood that the atom will gain an electron and become an anion. This value also generally increases from left to right on the periodic table as the effective nuclear charge increases thus will attract the electron greater and more energy will be released. Thus (C) is the correct answer.

Enols are generally stronger acids than alkyl alcohols of similar structure because: a) enols have a lower molecular weight b) enols have more electron-donating characteristic c) enols can resonance stabilize the deprotonated form d) enols are more reactive than alkyl alcohols

c) Reactivity does not directly correlate to acidity, making (D) incorrect. While it is true that they have a marginally lower molecular weight for a corresponding similar structure, molecular weight is also not directly correlated to strength of an acid. Enols, specifically the alkene groups, are considered electron-withdrawing groups (making (B) incorrect) due to their ability to resonance stabilize the enolate (deprotonated form). This makes (C) the correct answer.

How many carbon peaks would the molecule 3-ethyl-2-methylheptane show in its C-NMR? a) 7 b) 8 c) 9 d) 10

c) We may begin at the 1-carbon. This carbon and the methyl carbon off of the 2-carbon are identical. Then we have the 2,3,4,5,6 and 7 carbons being different. Then we have the extra two carbons from the ethyl group off of the 3-carbon, giving a total of 9 chemically different carbons

Medical school sometimes feels like a big, scary monster is chasing you through a park. To fend off this monster, students study furiously. They incrementally increase this behavior as the test approaches to ward off the potential unpleasant experience of bombing the exam. What is this an example of? A. Extinction B. Negative reinforcement C. Positive punishment D. Avoidance learning E. None of the above

d) Avoidance learning is exactly what is described in the stem: increasing a behavior to avoid an unpleasant future consequence. This makes D correct. Extinction is a decreased response to a conditioned stimulus when no longer paired with an unconditioned stimulus. This is not taking place here, eliminating A. Punishment, either negative or positive, leads to decreased behaviors in operant conditioning, not increased behaviors. Both B and C are incorrect.

Many double-displacement reactions are enzyme-catalyzed via the "ping pong" mechanism, so called because the reactants appear to bounce off the enzyme like a ping pong ball. These reactions typically have two reactants and two products. In a third-order reaction involving two reactants and two products, doubling the concentration of the first reactant causes the rate to increase by a factor of 2. What will happen to the rate of this reaction if the concentration of the second reactant is cut in half? a) It will increase by a factor of 2. b) It will increase by a factor of 4. c) It will decrease by a factor of 2. d) It will decrease by a factor of 4.

d) Based on the information given in the question, the rate is first-order with respect to the concentration of the first reactant; when the concentration of that reactant doubles, the rate also doubles. Because the reaction is third-order, the sum of the exponents in the rate law must be equal to 3. Therefore, the reaction order with respect to the other reactant must be 3 - 1 = 2. If the concentration of this second reactant is multi- plied by 1/2, the rate will be multiplied by (1/2)2 = 1/4.

Two sound waves vibrate such that a listener hears a beat frequency of 4 Hz. Which of the following is a possible frequency of the two waves? a) 448 Hz and 450 Hz b) 400 Hz and 800 Hz c) 400 Hz and 416 Hz d) 448 Hz and 452 Hz

d) Beat frequency is determined by the difference between two wave frequencies. For option (D), the difference is 452-448 = 4 Hz, thus (D) is the correct answer.

Which of the following describes a beta oxidation reaction? a) Glucose is converted to glycogen b) Glycogen is converted to glucose c) Protein is converted to alpha-keto acid d) Fatty acid is converted to acetyl-CoA e) Acetyl-CoA is converted to fatty acid

d) Beta oxidation is the process by which fatty acid molecules are broken down in the mitochondria to produce acetyl-coA, which can then enter the citric acid (Krebs) cycle. The correct transition from reactant to product for beta oxidation is fatty acid to acetyl-coA

Which of the following biochemical processes result in the production of beta-hydroxybutyrate? a) citric acid cycle b) pentose phosphate pathway c) gluconeogenesis d) ketogenesis

d) Beta-hydroxybutyrate is one of the major ketone bodies formed in the body during states of starvation or fasting (along with other medical conditions). Ketogenesis is responsible for the formation of this ketone body. Thus (D) is the correct answer.

A student creates a 1M citrate (C3H5O(COO)33-) buffer solution at pH 5.0. He then dilutes the solution to 200 mM, and adds it to his experiment. What is the pH of the 200 mM buffer solution? A. Between pH 5 and pH 7 B. Greater than pH 7 C. Less than pH 5 D. The pH will remain close to 5

d) Buffers are designed to maintain pH at a certain level, and operate through the complementation of a conjugate acid and base. As long as the ratios of acid and base remain the same in the buffer system, and they will no matter what the dilution, as long as the dilution is not very very small (i.e. 1 mM or less), the pH will remain the same.

Which of the following is true about histones? a) They allow for efficient transposition of gene segments. b) They aid in the proper reproduction of chromosomes. c) They manage the length of telomeres on chromosomes. d) They allow for efficient packaging of DNA within the nucleus.

d) Cells of higher organisms require efficient packaging of chromosomes within the nucleus. Such packaging allows the chromosomes to fit inside the nucleus and be replicated properly.

Which of the following is incorrect regarding countercultures? a) it is an example of a subculture b) Bohemianism may serve as an example of a counterculture c) it typically uses political means to accomplish goals d) its views typically align with cultural mores

d) Countercultures are subcultures with behaviors and ideas that differ significantly from the rest of society and do NOT align with cultural mores. Thus (D) is the correct answer.

Neural transduction occurs in which direction? a) Cell body, dendrites, axon b) Axon, dendrites, cell body c) Axon, cell body, dendrites d) Dendrites, cell body, axon

d) Dendrites often receive the nerve signal, which passes to the cell body and finally travels down the length of the axon. This nerve signal transduction creates a change in cell potential and is unidirectional.

Which of the following would represent the best example of deviance? a) A teenage girl getting her ears pierced without her parents' permission. b) A boy smoking marijuana because his friends are pressuring him to do so. c) A man takes three wives. d) None of the above behaviors can accurately be defined as "deviant".

d) Deviance is defined in relation to the cultural norms. Not enough information is available to conclude that the behaviors above are "deviant" within their respective cultures.

Which of the following atoms is expected to have the highest effective nuclear charge on the 1s electron? a) F b) Ne c) Cl d) Ar

d) Effective nuclear charge refer to the positive charge that a particular electron experiences. As we are evaluating the effective charge on the 1s electron in each atom, the atom with the highest number of protons (and thus positive nuclear charge) would have the highest effective nuclear charge on the 1s atom. Ar, option (D), has the largest number of protons in the nucleus, thus (D) is the correct answer.

Which of the following is NOT a method by which enzymes decrease the activation energy for biological reactions? a) Modifying the local charge environment b) Forming transient covalent bonds c) Acting as electron donors or acceptors d) Breaking bonds in the enzyme to provide energy

d) Enzymes are not altered by the process of catalysis. A molecule that breaks intramolecular bonds to provide activation energy would not be able to be reused.

Felix is a construction worker. He struggled to read as a child but he can move his body skillfully and learn new tools and techniques for his job. According to Gardner's multiple intelligence theory, which intelligence does this describe? a) Spatial b) Auditory-musical c) Linguistic d) Kinesthetic

d) Felix has a kinesthetic learning style. Kinesthetic learners tend to prefer using their hands, bodies and sense of touch for learning. Different people learn in different ways. Learning styles groups common ways that individuals learn. Many people use more than one learning style, but most people have 1 or 2 dominate learning styles.

All of the following quantities are vectors EXCEPT one. Which one is the EXCEPTION? A. Electric current B. Magnetic field C. Electric force D. Electric potential

d) Fields are vectors because they cause forces, and force is a vector. Current is a vector because charge can flow in either direction in a wire. However, electric potential is related to potential energy (PE = qV), and all forms of energy are scalar quantities.

What voltage would be expected in a circuit with a total resistance of 15 ohms and a current of 15 amps? a) 1 V b) 30V c) 15V d) 225V

d) From the expression V=IR, we can calculate that the voltage will be 15*15 = 15, thus (D) is the correct answer.

Which of the following concepts are LEAST likely to coincide? a) Hazardous waste facilities and low-income neighborhoods b) Tuberculosis and poor living conditions c) Environmental pollution and high minority population d) Globalization and global equality

d) Globalization does not typically lead to global equality; rather, globalization tends to create further global inequalities. In regard to environmental justice, higher numbers of hazardous waste facilities tend to be found in low-income neighborhoods, choice (A). Poor living conditions tend to be associated with greater health problems, including tuberculosis, choice (B). Finally, environmental pollution is more prevalent in areas with minority populations, especially low-income minority populations, choice (C).

Which of the following would be most likely processed by Golgi bodies? a) nucleic acids b) ribosomes c) ATP d) polypeptides

d) Golgi bodies are largely responsible for the processing of polypeptides into functional proteins. They aid in the process of folding, glycosylation, and direction of the proteins to their final destinations.

Homo sapiens as well as homo erectus are scientific classifications for two species both considered broadly to be humans. These two animals differ among which of the following: I. phylum II. family III. genus IV. species a) I, II and III b) II, III and IV c) III and IV d) IV

d) Homo sapiens and homo erectus differ only in terms of species and are in the same genus and all phylogenetic terms higher in the hierarchy. This (D) is the correct answer.

Infrared spectroscopy is performed for a molecule and a broad peak is noted at around 3300 cm-1. Which of the following functional groups would be expected within this molecule? a) aromatic b) amine c) aldehyde d) hydroxyl

d) Hydroxyl groups (-OH) form broad peaks at around 3300 cm-1 on infrared spectroscopy (IR). Thus (D) is the correct answer.

A solution contains a variety of organic, nonpolar molecules, including strong and weak acids and strong and weak bases. An extraction experiment is held, with a weak acid being added to the solution. Which of the following molecules would be expected to be extracted after draining the aqueous layer of the solution after the weak acid is added? a) weak acids b) weak bases c) strong acids d) strong bases

d) In extraction, various acids and bases can be added to a solution in order to extract molecules from the solution. In this example, a weak acid is added. This weak acid would be expected to react with only the strongest of bases, in the sense that the strong bases would become protonated from the acid; in becoming protonated, these bases would become polar and would form an aqueous layer in the solution, which could then be drained off. Thus (D) is the correct answer.

A student plans on performing a liquid-liquid extraction to isolate an analyte from aqueous solution into acetone. Which of the following will most likely result from this experimental setup? a) The extraction will work because organic solvents are not miscible with water. b) The extraction will work because solvent choice is not relevant to liquid-liquid extraction efficiency. c) The extraction will not work because the analyte is not soluble in acetone. d) The extraction will not work because the solvents are miscible

d) It is simply untrue that organic solvents are not miscible with water. While some are not, many are miscible, including acetone. This eliminates (A). (B) is incorrect because solvent choice is incredibly important to the efficiency of extraction, as it determines relative solubility of the analyte between the solutions. (C) is incorrect because we lack sufficient information to determine whether or not the analyte is soluble in acetone. (D) is the correct answer, because miscible solvents will not be able to form separate layers for extraction; the student would simply end up with a single homogeneous solution and be no closer to extracting analyte than before the experiment.

Organelles such as mitochondria, nuclear membrane, and the endoplasmic reticulum are found in which of the following types of organisms? a) Archaea b) Bacteria c) Viruses d) Protists

d) Mitochondria, a nuclear membrane, and the endoplasmic reticulum are specific to eukaryotic organisms. Of the four listed, the only eukaryotes are the protists.

In the peripheral nervous system, which cell myelinates and in turn increases the action potential across a nerve axon? a) Microglial cell b) Oligodendrocyte c) Astrocyte d) Schwann cell

d) Oligodendrocytes provide myelination in the central nervous system but not the peripheral nervous system. Astrocytes and microglial cells are support cells that clean debris from tissue surrounding nervous tissue. Schwann cells are the myelination cells of the peripheral nervous system, and thus (d) is the correct answer.

What is the volume of two moles of diatomic nitrogen gas at STP? a) 22.4L b) 33.6L c) 11.2L d) 44.8L

d) One mole of gas has a volume of 22.4L at STP since there are two moles of gas present, the volume is doubled. 2(22.4) = 44.8L the fact that the gas is diatomic is irrelevant

Strecker synthesis is used in the synthesis of: a) fats. b) hydrocarbons. c) nucleic acids. d) amino acids.

d) Strecker synthesis is a set of chemical reactions which produce amino acids from aldehydes or ketones. Thus (D) is the correct answer.

What would be the result of increased levels of parathyroid hormone (PTH)? a) Decreased blood potassium b) Decreased blood calcium c) Increased blood potassium d) Increased blood calcium

d) Parathyroid hormone is secreted by the parathyroid glands, and acts in a few ways to directly and indirectly increase blood calcium levels. Parathyroid hormone increases calcium reabsorption in the collecting tubule of the kidney, increasing calcium absorption in the gut, and increasing bone resorption to free stored calcium. Parathyroid hormone and calcitonin act in a negative feedback loop to maintain calcium levels, Calcitonin is released from the thyroid, and serves to decrease blood calcium. Maintaining blood calcium levels is particularly important because heart attacks can become common in low calcium settings, as calcium is crucial to maintaining cardiac muscle contractions

The endocrine system is composed of glands, which secrete hormones directly into the blood. After traveling to a distant target, they induce a change in gene expression or cellular functioning. There are several classes of hormones, including peptide hormones, steroid hormones, and amino-acid derivative hormones. What is not true of peptide hormones? A. They are charged B. They cannot pass through the membrane C. They act as the 1st messenger D. The effects are slower, but longer-lived than steroid hormones E. They can travel without a carrier in the blood stream

d) Peptide hormones are charged (just think about the fact that amino acids are charged) and consequently cannot penetrate the cell membrane. This eliminates A and B. Since they cannot pass through the membrane, they bind to an extracellular receptor, thereby acting as the 1st messenger. The 2nd messenger is the second, intracellular signal to follow. This eliminates C. Actually, D is reversed. The effects of peptide hormones are quicker and shorter-lived than steroid hormones. This is because steroid hormones cause alternations in the quantity of mRNA and protein present in a cell, which as you can imagine, would take longer to initiate and have a more lasting effect on the cell. This makes D the correct answer. Last, since they are water-soluble, they are able to travel in the bloodstream without a carrier. This rules out E.

What role does peptidyl transferase play in protein synthesis? a)It transports the initiator aminoacyl-tRNA complex. b) It helps the ribosome to advance three nucleotides along the mRNA in the 5′ to 3′ direction. c) It holds the proteins in its tertiary structure. d) It catalyzes the formation of a peptide bond.

d) Peptidyl transferase is an enzyme that catalyzes the formation of a peptide bond between the incoming amino acid in the A site and the growing polypeptide chain in the P site. Initiation and elongation factors help transport charged tRNA molecules into the ribosome and advance the ribosome down the mRNA transcript, as in choices (A) and (B). Chaperones maintain a protein's three-dimensional shape as it is formed, as in choice (C).

How does prokaryotic DNA differ from eukaryotic DNA? I. Prokaryotic DNA lacks nucleosomes. II. Eukaryotic DNA has telomeres. III. Prokaryotic DNA is replicated by a different DNA polymerase. IV. Eukaryotic DNA is circular when unbound by centromeres. a) I only b) IV only c) II and III only d) I, II, and III only

d) Prokaryotic DNA is circular and lacks histone proteins, and thus does not form nucleosomes. Both prokaryotic and eukaryotic DNA are replicated by DNA polymerases, although these polymerases differ in identity. Eukaryotic DNA is organized into chromatin, which can condense to form linear chromosomes; only prokaryotes have circular chromosomes. Only eukaryotic DNA has telomeres.

The aorta of a 70 kg man has a cross section area of 3 square centimeters and carries blood with a velocity of 30 centimeters per second. What is the average volume flow rate? A. 10 cm3/s B. 33 cm3/s C. 66 cm3/s D. 90 cm3/s

d) Q = Av = (3.0 cm2)(30 cm/s) = 90 cm3/s.

If you forget to leave a gold pendant in front of the fireplace (it weighs 10 kg) and it absorbs heat at a rate of 150 W for 15 minutes, what will its final temperature be? Assume the pendant begins at 20 degrees Celsius and the specific heat of gold is 200 J / (kg x K) . A. 80 degrees Celsius B. 82.5 degrees Celsius C. 85 degrees Celsius D. 87.5 degrees Celsius E. 90 degrees Celsius

d) Remember, watts are equal to joules per second. Another way to think of it is energy transfer over time. Therefore, in the 15 minutes, the pendant absorbs the following: Power (watts) = Work (joules) / time (second) Energy = Power x time = (150 W)(15 min)(60s/1min) = 1.35 x 10^5 J Then, the final temperature can be found with this equation: q = mc∆T q = energy gained m = mass c = specific heat ∆T = temperature change 1.35 x 10^5 J = (10 kg)(200 J/ (kg x K))∆T ∆T= 67.5 degrees Celsius (the scales for kelvin and celsius are the same) Therefore, the final temperature is 87.5 degrees Celsius.

Assume that in a certain flower population, there is only one gene for color. White is dominant over blue. 49% of the population is homozygous dominant. What percentage of the flower population are heterozygotes? Assume that the population is in Hardy-Weinberg equilibrium. a) 49% b) 51% c) 58% d) 42%

d) Since 49% of the population is homozygous dominant, we know that 70% of the population has the dominant allele. This directly follows from the Hardy-Weinberg equilibrium equation that p2=homozygous dominant (i.e. p2 = 0.49, therefore p 0.70) Since 70% of the population has the dominant allele, that means that 30% of the population has the recessive allele. We can find what percentage of the flower population are heterozygotes by multiplying these values together and doubling them (remember p2+2pq+q2). Therefore we get 2(0.7)(0.3) = 0.42.

Which of the following work-related activities may be most prone to social loafing? a) leading a meeting in front of colleagues b) cleaning one's office cubicle c) sending a divisive email to a project manager d) working as part of a larger group to complete a time-sensitive project

d) Social loafing refers to the phenomenon where individuals exert less effort when working as part of a group than when working individually. The only option that aligns with a group activity is option (D).

Because physicists and chemists classify the world on the basis of observable phenomena, they created the terms isolated systems, closed systems, and open systems. Isolated systems can exchange neither energy or matter. Closed systems are capable of exchanging only energy, while open systems can exchange both matter and energy. Which of the following is not a state function? A. Pressure B. Temperature C. Internal energy D. Work E. Entropy

d) State functions are those that are a function of the current equilibrium state. Another way to say this is that they are independent of the path taken to get to a certain equilibrium state. They include pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, and entropy. On the other hand, process functions, as the name would suggest, describe and depend on the path taken to get from one state to another. These are work and heat. This makes D the correct answer.

Simultaneous processing of conscious emotions and physiological activation is the defining feature of which theory of emotion? a) Schachter-Singer theory b) James-Lange theory c) Incentive theory d) Cannon-Bard theory

d) The Cannon-Bard theory of emotion is based on the premise that conscious feelings and physiological components of emotion are experienced at exactly the same time. In this theory, this combination then leads to action. This is commonly confused with the Schachter-Singer theory, choice (A), in which nervous system arousal occurs and then is labeled based on the context provided by the environment.

T-cells use receptors in their activity to defend their biological hosts. These receptors are protein molecules, heavily modified before being sent to the cell's surface. In which organelle does the majority of such modification take place? a) Nucleolus b) Lysosome c) Smooth endoplasmic reticulum d) Golgi apparatus e) Ribosomes

d) The Golgi apparatus is the organelle tasked specifically with the modification of proteins. Membrane proteins are synthesized by ribosomes of the rough endoplasmic reticulum before being sent to the Golgi apparatus for modification and packaging. This packaging allows for integration of the receptor proteins into the membrane

Which statement correctly characterizes the Nodes of Ranvier? a) They are insulated by myelin sheaths. b) They are insulated by Schwann cells. c) They possess a double membrane used for developing a proton motive force for action potentials d) They possess gated Na and K channels involved in action potentials

d) The Nodes of Ranvier are exposed sections of the axon which lie between Schwann cells. The Nodes of Ranvier help propagate action potentials along the axon very quickly by regulating their Na and K channels.

How many molecules of NADH are produced from 2 glucose molecules through the citric acid cycle? a) 6 b) 8 c) 10 d) 12

d) The citric acid cycle produces 1 ATP, 3 NADH, and 2 CO2 per acetyl-CoA molecule. Each glucose provides two acetyl-CoA molecules, thus 4*3 = 12 NADH molecules. Thus (D) is the correct ans

The electron configuration [Ne]3s23p6 is the structure of: a) krypton. b) sulfur atom. c) argon cation. d) chloride anion.

d) The electron configuration displayed the configuration for the chloride anion (Cl-). Thus (D) is the correct answer.

For those atoms in the first column of the periodic table which form stable positive ions, the ion usually has a considerably smaller radius than the neutral atom. What explains this effect? A. The outer electron(s) effectively screen the nuclear charge. B. The ion has a greater nuclear charge. C. The neutral atom has a greater nuclear charge. D. The neutral atom has an outer electron in an orbital of higher "n" than the ion.

d) The electron in the neutral atom occupies an s orbital of higher n than the valence electrons of the positive ion. The former electron will stay, on average, farther from the nucleus than the inner electrons.

Jean Piaget is an influential figure in developmental psychology. He was adamant that there are distinct qualitative differences between the way children and adults think, ultimately dividing the human lifespan into four stages of cognitive development. What is the correct ordering of these stages, youngest to oldest? A. Sensorimotor, preoperational, formal operational, concrete operational B. Sensorimotor, formal operational, preoperational, concrete operational C. Preoperational, sensorimotor, concrete operational, formal operational D. Sensorimotor, preoperational, concrete operational, formal operational E. None of the above

d) The first stage, sensorimotor, begins at birth and lasts until about two years of age. In this stage, the child is learning to manipulate his or her environment to meet physical needs. This stage ends with the key developmental milestone that is object permanence, or the understanding that objects continue to exist even when out of view. Then, the preoperational stage lasts from about two to seven years of age. This period includes symbolic thinking, egocentrism, and centration. Egocentrism is the ability to imagine what another person may think or feel, while centration is is the inability to understand the idea of conservation. A child presented with two identical quantities of pizza, one plate has a single large piece, while the other plate has this cut in half, will be unable to tell that they are actually equal. Then, the concrete operational stage lasts from seven until eleven. Children now understand conversation and consider the viewpoints of others. Moreover, they can engage in logical thinking. The formal operations stage begins at the age of eleven and extends thereafter. It is marked by logical thinking about abstract ideas.

If you desire to prevent the initial enzymatic breakdown of polysaccharides, where in the body should the release of such enzymes be blocked? A. In the mouth, stomach, pancreas, and small intestine B. In the mouth, stomach, and pancreas C. In the mouth, pancreas, and small intestine D. In the mouth and pancreas

d) The initial breakdown of polysaccharides to disaccharides is in the mouth via salivary amylase and pancreatic amylase via the pancreas to the small intestine. We do not block the small intestine since the pancreatic amylase is not produced there, we block the source as the question wanted to know how to block the enzyme.

A penny is thrown horizontally with an initial speed of 20 m/s. How far will it drop in 5 seconds? (Ignore air resistance). A. 45 m B. 65 m C. 75 m D. 125 m

d) The initial horizontal speed is irrelevant. Use this equation: x = (1/2)g(t)2 = (1/2)(10)(5)2 = 125 m.

There are potential risks associated with advancing biotechnology. For instance, safety concerns, like as increased resistance in viruses and bacteria can have negative effects on both us, as humans, and our environment. Ultimately, ethical questions arise, like is it ethical to test for potentially life-threatening genetic diseases and potentially terminate a pregnancy based on the results? Which of the following DNA sequences would have the highest melting temperature? A. CATAACAAATCA B. CGTAATAATACA C. CGCAATAATACA D. CGCAACCATCCG E. C and D would be equivalent

d) The melting temperature of DNA refers to the temperature at which the DNA double helix denatures into two single strands. This requires the hydrogen bonds linking the base pairs to be broken. Remember, cytosine binds to guanine with three hydrogen bonds, while adenine binds to thymine with two hydrogen bonds. Ultimately, the heat required to disrupt the bonds is proportional to the number of bonds present. Essentially, we are looking for the highest GC content, which is present in D. This makes it the correct answer.

Two point charges attract each other with a force of 3.6 x 10-6 N when they are 3 m apart. What is the force if the distance is increased to 6 m? A. It is tripled. B. It is reduced to one-ninth. C. It is quadrupled. D. It is quartered.

d) The force is inversely proportional to the square of the distance between the point charges. Since the distance is doubled, the force must be quartered.

Which of the following would be affected by a mutation in the actin protein? I. Mitosis II. Muscle contraction III. Cellular shape a) II only b) II and III only c) I and III only d) I, II and III

d) The mitotic spindle is mediated in part by actin which helps to control the spindle's length, supporting the microtubules. Muscle contraction is mediated by both myosin and actin. Cellular shape is largely determined by the cytoskeleton whose primary component is actin. Therefore all three will be affected by changes to actin.

Hashimoto's thyroiditis is characterized by an enlarged thyroid gland, with only one side being palpable. The disease course includes cells of the thyroid becoming inefficient at converting iodine into thyroid hormone. They compensate by enlarging. Paradoxically, radioactive iodine uptake may be high while a patient is hypothyroid because the gland remains able to take up iodine, despite its inability to produce thyroid hormone. Which one of the following would you not expect in hypothyroidism? A. Lethargy B. Decreased body temperature C. Slowed respiration and heart rate D. Cold tolerance E. Weight gain

d) The only incorrect symptom is cold tolerance. The patients actually exhibit cold intolerance. On the other hand, hyperthyroidism is characterized by the opposite: heightened activity, increased body temperature, increased respiration and heart rate, heat intolerance, and weight loss.

lf ATP synthesis was inhibited in the nervous system of an animal, which of the following best describes the major effect on neural function? a) The cell could not generate an action potential b) The cell could not propagate action potentials throughout its membrane c) The cell could not open voltage-gated channels d) The cell could not maintain its resting potential

d) The resting potential is the imbalance of electrical charge that exists between the interior of a cell and its exterior, and this is influenced mainly by sodium and potassium ions. At rest, there are relatively more sodium ions outside the cell and more potassium ions inside the cell. Because of the high permeability for potassium, the resulting membrane potential is usually close to the potassium reversal potential. In order for this imbalance to even occur, a concentration gradient is established, which is done by ion pumps/transporters that are powered by ATP. In the case of the resting membrane potential across an animal cell's membrane, potassium and sodium gradients are established by the sodium-potassium pump, which transports three sodium ions outside and two potassium ions inside, at the cost of 1 ATP molecule. If ATP synthesis was inhibited (for example, due to some inhibitor blocking ATP Synthase), this sodium-potassium pump would be compromised, as there is not enough ATP available to maintain a resting potential

Which of the following is an accurate statement regarding sodium-potassium pump? a) the pump functions through facilitated diffusion b) ATP is not required for its function c) it moves potassium and sodium ions in equal amounts across the plasma membrane d) it moves sodium from a lower concentration to a higher concentration

d) The sodium-potassium pump (also called sodium-potassium ATPase) is an enzyme found in plasma membranes and moves sodium and potassium in non-equal amounts across the plasma membranes such that the ions move against the concentration gradient. Thus option (D) is the correct answer.

Which of the following molecules has a dipole moment? a) CCl4 b) BF3 c) CO2 d) SO2

d) The sulfur in SO2 has a pair of localized electrons around it, thus giving it a bent shape. Unlike CO2, which has a planar shape, the dipole does not cancel out and SO2 has a dipole moment.

Carboxylic acids are found in soaps, oils, preservatives, skin care products, clothing, and amino acids. They often have unpleasant odors. Acetic acid is the main ingredient in vinegar. Propionic acid gives Swiss cheese its pungent smell. Butyric acid is in both rancid butter and body odor. Which of the following carboxylic acids is the least acidic? A. CH3CHClCH2COOH B. CH3CH2CCl2COOH C. CH3CH2CHClCOOH D. CH3CH2CH2COOH E. D and A are equally acidic

d) The underlying factor here is the presence of highly electronegative functional groups. Their electron withdrawing capabilities stabilize the subsequent carboxylate anion, pushing equilibrium toward proton dissociation. This increases with the number of electronegative groups on the molecule, also being impacted by their distance from the acid functionality. Therefore, the answer choice without a electronegative functional group is clearly the least acidic.

An increase in the motion of molecules of a gas confined in a metal tank will be observed as an increase in: A. the pressure of the gas only. B. the temperature of the gas only. C. the temperature of the gas and a decrease in its pressure. D. both the temperature and pressure of the gas.

d) The word "kinetic" means movement or motion. An increase in motion means that there is an increase in kinetic energy which we know is directly related to temperature (CHM 4.1.2). When there is an increase in motion, that means there is an increase in the force of the molecules hitting the walls of the container. Pressure is force per unit area (PHY 6.1.2) so the pressure must increase if the motion increases.

A particular mutation results in a defect in production of a zona pellucida in a particular female population. Which of the following effects might this have? a) decreased propensity for ovulation b) increased weight of an ovum c) increased likelihood for uterine cancers d) decreased ability of the egg to bind spermatozoa

d) The zona pellucida is a glycoprotein coating around oocytes which is responsible for binding spermatozoa and is critical for fertilization. Thus (D) is the correct answer.

A mutation in neurons is such that it prevents myelin from being formed in the peripheral nervous system along its axons. It is likely that a) these axons have fewer sodium-potassium channels than regular neurons b) this individual has decreased quantity of oligodendrocytes c) the axons have increased conduction velocity d) the axons induce identical amplitude action potentials as normal neurons

d) This question may be difficult and needs to be solved with process of elimination. (A) is incorrect because these channels would not be affected. (B) is wrong because oligodendrocytes are in the CNS, not PNS. And (C) is incorrect because conduction velocity would be decreased. Even though conduction velocity decreases, the actual amplitude of the action potential remains the same, it just takes longer for that signal to reach other neurons. Thus (D) is the correct answer.

Which of the following is not a shape of bacteria? a) round b) spiral c) rod-shaped d) triangular

d) Typical shapes for bacteria include: round (cocci), rod-shaped (bacilli), and spirals (which include spirochetes, vibria organisms). Option (D) is the only option which is not a shape that bacteria take.

Combustion reactions always involve molecular oxygen, O2. Anytime anything burns, it is undergoing a combustion reaction, which is almost always exothermic. An example is methane converted to carbon dioxide and water. What other reactions have the same number of reactants and products, in general? I. Double-displacement reactions II. Single-displacement reactions III. Combination reactions IV. Oxidation-reduction reactions A. I only B. II only C. I, II, III D. I, II, IV E. None of the above

d) Typically both single-displacement and double-displacement reactions have two reactants that swap either one or two components between the two species. This makes I and II correct. On the other hand, combination reactions have more reactants than products since the reactants come together to form the products. This eliminates III. Oxidation-reduction reactions can be thought of as synonymous with single displacement reactions. Here is an example of one: 3AgO3 + 2 Al -> 3 Ag + Al2O3. Aluminum is the reducing agent here and as you can see, the number of reactants and products is equal. This makes IV correct too. Ultimately, only D reflects this.

Tanning in the sun is often associated with the sensation of heat on the skin. This sensation is similar to the sensation when close to a hot fire or oven. Yet, the hot fire and oven do not induce the same changes in skin coloration. The fact that fires and ovens do not darken the skin is primarily due to the fact that a) One does not expose him or herself to fires and ovens as long as to the sun; this is the only reason why the skin does not get dark. If one were to expose him or herself for a longer period of time, the same effects would be seen as if one had been in the sun. b) Fires and ovens do not emit enough infrared radiation to induce the changes necessary to darken skin color. c) Fires and ovens are not hot enough to induce color changes in skin. d) Fires and ovens do not emit the correct wavelength of electromagnetic radiation to induce the chemical changes in the skin to darken it.

d) Ultraviolet radiation causes the changes to skin color. Skin cells produce more dark-colored melanin to help absorb the UV radiation. Heat, however, in terms of electromagnetic radiation, is known to be in the infrared range of light. Hence answers B and C are incorrect. A is incorrect because in fact, one cannot get tanned by exposure to normal ovens and fires as they do not emit ultraviolet radiation which is necessary for the production of melanin.

Decarboxylation describes the complete loss of the carbonyl group. This is a very common way of getting rid of a carbon from the parent chain. Under heat, what compounds spontaneously decarboxylate? A. 1,3 dicarboxylic acids B. Beta-keto acids C. Beta-diketones D. A and B E. A, B, and C

d) Under heat, both 1,3 dicarboxylic acids and beta-keto acids spontaneously decarboxylate. Ultimately the carboxyl group is lost and replaced with hydrogen. Since the electrophile and nucleophile reside in the same molecule, the reaction proceeds through a 6 membered ring in its transition state. Then, the formed enol tautomerizes to the more stable keto form.

A mutation is discovered which results in the myelin sheath overgrowing and covering all the space along the axon where there would normally be Nodes of Ranvier. Which of the following would be expected of such a neuron? a) close-to-normal functioning as Nodes of Ranvier are not an essential component of signal propagation down an axon b) repeated spontaneous depolarization and signal transmission down the axon c) inability to be stimulated by an action potential d) inability to propagate an action potential down the axon

d) Unmyelinated neurons have their entire axons exposed and thus have no Nodes of Ranvier. However, myelinated neurons can propagate their signals only via the Nodes of Ranvier which are the only exposed areas of the axon membrane. If those nodes were covered, the action potential would be unable to propagate down the axon, making (D) the correct answer. (C) is incorrect because while propagation would be prevented, stimulation would not; the neuron can be stimulated at the dendrites and the nerve cell body, and stimulation does not require propagation within the stimulated cell.

Which of the following cell types does not contain a non-zero resting membrane potential? a) Neuron b) Cardiomyocyte (heart muscle cell) c) Pancreatic cells d) All cells have non-zero membrane potentials

d) While many may think of the only cells as having membrane potentials as neurons or other cells that produce action potentials (such as muscle cells), that is an incorrect view of membrane potentials. In fact, virtually all cells in the body have a non-zero resting potential. This is due to the fact that the extra-cellular environment contains a significantly larger amount of sodium than the intracellular environment. This causes the intracellular environment to be more negative than the outside environment, thus most cells have a negative resting charge. Thus (D) is the correct answer.

The spinal cord is composed of two structurally different tissues. Gray matter lies internal to white matter in the spinal cord. What accounts for the differences in color of these two tissues? a) White matter is mainly composed of oligodendrocytes, which appear white to the naked eye. b) Gray matter is much more highly condensed, giving it a gray look. c) White matter axons are not myelinated while gray matter axons are. d) Gray matter axons are not myelinated while white matter axons are.

d) White matter axons are myelinated, and it is specifically the myelin that makes the white matter appear white. The gray matter is unmyelinated, and thus this white-color phenomenon does not occur.

Phylloquinone and menaquinone are the common names for vitamins K1 and K2, respectively. They are fat soluble vitamins that play a role in carboxylation of clotting factors II, VII, IX and X. If you wanted to convert p-benzenediol to 1,4-benzoquinone, what compound would you use? A. LiAlH4/NaBH4 B. LiAlH4/ether, followed by H+/H2O C. mCPBA D. Na2Cr2O7/H2SO4 E. None of the above

d) You don't need to picture the exact formulation of the molecules in the question stem. You just need to know that you are going from a secondary alcohol to a ketone. This is therefore oxidation. A and B are both reducing agents, reducing aldehydes to primary alcohols and ketones to secondary alcohols, respectively. C is eliminated as well because mCPBA creates epoxides. Ultimately, D is the correct answer.

Which of the following is a common barrier to healthcare access for transgender individuals? a) Refusal of care b) Harassment or assault in a medical setting c) Lack of provider knowledge d) All of these

d) a 2010 survey conducted by the national center for transgender equality and the national gay and lesbian task force collected the following findings: 50% of transgender or gender non-conforming individuals surveyed stated that their provider had very little or no knowledge of transgender care, 19% were refused care outright (including for conditions that did not relate to gender transition), and 28% reported experiencing harassment in a medical setting - with 2% reporting assault or some other act of violence perpetrated against them in a doctor's office

Which of the following is true regarding Archimedes' principle? I. It states that the weight of an object is equal to the weight of liquid it displaces II. It states that the buoyant force increases as the density of the object in the fluid increases III. It is not applicable for an object that is completely submerged in a liquid a) III only b) I and II c) II and III d) I only

d) archimedes' principle states that the upward buoyant force experienced y a solid object in a fluid is equal to the weight of the fluid displaced. In mathematical form, Archimedes' principle states B = Mfluiddisplaced x g B = buoyant force, Mfluiddisplaced = mass of the fluid displaced, g = acceleration due to gravity. Recall that density is defined as mass divided by volume; therefore, mass of fluid can be written as: Mfluiddisplaced = pfluid x Vfluiddisplaced pfluid = density of fluid and Vfluiddisplaced = volume of fluid displaced. Plugging this equation into Archimedes' principle gives: B = pfluid x Vfluiddisplaced x g Notice that the density of the object is not part of Archimdes' principle; therefore, the density of the object doesn't affect the buoyant force. Both submerged and floating objects in a fluid will experience an upward buoyant force that is equal to the weight of the fluid displaced; Archimedes' principle is valid for both submerged and floating objects

A pendulum is under simple harmonic motion and has a mass (10 kg) attached to it. By increasing the mass to 20 kg, how is the period affected? a) Decrease b) Increase c)Need more information to answer this question d) Remain the same

d) as you can see from the period equation (period = 2(pi)(square rootL/g) where g is gravity and L is the length of the pendulum, the mass has no effect on the period

Which of the following is false regarding a battery? a) Recharging a battery involves a nonspontaneous chemical reaction b) A battery houses two electrodes: the anode and the cathode c) Electrons are reactants at an anode, and are products at a cathode d) A battery converts chemical energy into electrical energy

d) batteries are a series of electrochemical cells that use the electrical energy associated with the movement of electrons to perform other processes. The electrical energy is not itself usable; instead, batteries convert the electrical energy into other forms of energy, such as chemical energy, that can be used to drive a process. The electrical energy is derived from the movement of electrons associated with redox reactions batteries contain one or more electrochemical cell. Each electrochemical cell houses a cathode and an anode, which facilitate a redox reaction. The cathode is the site of the reduction half-reaction, whereas the anode is the site of the oxidation half-reaction. Reduction is the process by which reactants gain electrons and become more negative; oxidation is the process by which reactants lose electrons and become more positive. As such, electrons are products at an anode and reactants at a cathode. The redox reaction proceeds in the spontaneous reaction direction when the battery is being used, but proceeds in the nonspontaneous reaction direction when the battery is being recharged after use. Recall that nonspontaneous reactions require energy. When you are charging a battery, you are supplying energy in the form of voltage to drive the nonspontaneous reaction. On the other hand, ,when you are discharging (or using) the battery, the spontaneous redox reaction is supplying energy to drive another process

What class of element is zinc? a) Alkali metal b) Non-metal c) Metalloid d) Transition metal

d) in general, the metals fall on the left side of the periodic table and are separated from the non-metals by the metalloids. Transition metals fall in the d block of the periodic table, in groups (columns) 3-12. Examples of metals, non-metals, transition metals, and metalloids are calcium, oxygen, zinc, and arsenic, respectively. Alkali metals are a special class of metal only found in group 1 of the periodic table

A 10kg object is originally at rest on an inclined plane, which forms an angle with the ground of 30o. If the coefficient of static friction is 0.2, what is the force of friction that must be overcome for the object to begin moving? a) 2.5N b) 19.3N c) −6.9N d) −17.0N e) 19.6N

d) in this situation, we must simply remember how to calculate friction. Once the force of gravity overcomes the force of static friction, the object will slide. our formula for friction is Fs = (mew)sN this means the force of friction is equal to the friction coefficient times the normal force. On an incline, the normal force is equal to the force of gravity times the cosine of the angle: FN = Fgcos(theta) Fg = mg we can combine our formulas to give the force of friction Fs = (mew)s(mg)(costheta) using the given coefficient of friction, mass, and angle, we can calculate the force of friction Ff = (0.2)(10kg)(-9.8m/s^2)(cos30) Ff = -16.97N

Which of the following INCORRECTLY pairs a digestive hormone with its function a) Trypsin - hydrolyzes specific peptide bonds b) lactase - hydrolyzes lactose to glucose and galactose c) pancreatic amylase - hydrolyzes starch to maltose d) lipase - emulsifies fats

d) lipase is involved in the digestion of fats, but its function is not to emulsify fats - this is the job of bile. rather, lipase chemically digests fats in the duodenum, allowing them to be brought into duodenal cells and packaged into chylomicrons. The other associations given here are all correct

Which of the following is not a Lewis acid? a) Al3+ b) NH+4 c) BF3 d) CaO e) Na+

d) the definition of a lewis acid is an electron acceptor. when the lewis dot structures are drawn, you will find that NH4+, Na+, and Al3+ are missing electrons. They each have an empty orbital, allowing them to accept electrons. BF3 is not an ion; however, we know that boron only has 3 valence electrons, which means that even when they are all bound to fluorine the molecule does not satisfy the octet rule BF3 only has 6 valence electrons around obron, and can accept another electron pair to get to the octet state. CaO is a lewis base. In the lewis dot structure, we can see that the oxygen molecule has two lone pairs that it can donate to other molecules, making it an electron donor.

The frequency of a pendulum on Earth is measured to be 10Hz. What will be the approximate frequency of the same pendulum on the moon? Approximate gravity on moon is 1.62ms2. a) 10Hz b) 10/6Hz c) 10√6Hz d) 10/√6Hz

d) the frequency of a pendulum is given by the relation f √g/L since gravity on the moon is one sixth of the gravity on earth, frequency on the moon will be √1/6 that on earth FE = √g/L FM = √1/6 x Fe If the frequency on earth is 10Hz, then the frequency of this pendulum on the moon is 10/√6 Hz

SO42- is most similar in molecular geometry to: a) PCl5 b) H2O d) SCl2 d) CH4

d) The molecular geometry of SO42- is tetrahedral due to having 4 substituent groups and no lone pairs. The only molecule listed that matches this structure would be CH4. Although the electronic geometry of SCl2 would be tetrahedral as well, its molecular geometry is bent due to the exclusion of the lone pairs.

The liver primarily serves to help detoxify both endogenous and exogenous substances from the blood and intestines. Once blood from the intestines (delivered by the portal vein) or from the systemic circulation (delivered by the hepatic artery) enters the liver, it is filtered over liver cells called hepatocytes. Endogenous substances, such as bilirubin, and exogenous substances, such as drugs, are taken up by transporters on hepatocytes and undergo three phases of metabolism. The three phases allow the transported compound to be detoxified by a method of electron transfer (phase I), by addition of amino acid derivatives (phase II), and finally by exocytosis from the hepatocyte into the bile (phase III). The bile is then transported into the small intestine, and finally excreted from the body. Amino acid derivatives are often taken from the Krebs cycle, added to sugar nucleotides, and transferred to molecules for detoxification. A common example of an enzyme responsible for this is UDP-glucuronosyl transferase. The flow of substances through the liver follows the portal triad. The portal triad does not include which of the following structures? a) Hepatic artery b) Bile duct c) Portal vein d) Central vein

d) the passage details the passage of substances through the liver. The portal triad consists of the portal vein, hepatic artery, and bile duct. Blood from the intestines enters the liver through the portal vein and is filtered by hepatocytes on its way to the central vein that connects to the inferior vena cava and onto the rest of the venous circulation. The liver is thus able to filter out toxic metabolites before they reach systemic circulation

Meiosis II occurs for the production of sex cells (sperm and eggs). For the egg, meiosis II actually occurs after the egg is fertilized by a sperm. Which of the following would not be expected to be found within the egg cell membrane after this meiosis process takes place? a) Sperm DNA b) Two polar bodies c) Enzymes from the sperm d) The zona pellucida

d) the zona pellucida lies outside of the egg cell membrane. It is a glycoprotein layer the sperm must pierce in order to get into the egg cell. All of the components would be expected to be found. There would clearly be sperm DNA because meiosis II occurs post-fertilization. There would also be two polar bodies - one is formed after meiosis I and one after meiosis II. Similarly, sperm enzymes might be expected to be found because those enzymes were used for the sperm to penetrate and get into the egg cell.

A 1.0kg block slides along a smooth surface at a velocity of 2ms. The block then encounters a rough surface and continues for six meters before coming to a complete stop. What is the force of friction on the block? a) 1/6 N b) 0 N c) 6 N d) 1/3 N e) 3 N

d) this question can be answered using conservation of energy. having an understanding of the work-energy theorem allows us the knowledge that changing kinetic energy is a form of work, and that work can be a form of energy. In this particular question, the only force acting on the block to slow it down is the force of friction from the rough surface. As we know, work is equal to force times distance. W = Fd. because the block started with a certain amoung of kinetic energy, and then is brought to a complete stop, all of that kinetic energy is transferred to work done by the force of friction over a distance of six meters. W = deltaKE = 1/2m(deltaV)^2 Because the 1 kg block had a velocity of 2m/s on a smooth surface and ends with a velocity of 0m/2 at rest, we can calculate the change in kinetic energy deltaKE = 1/2(1kg)(0m/s-2m/s)^2 = 2J The kinetic energy is completely converted to the work done by friction W = KE = 2J We can then use the first equation for work to determine the force of friction W = Fd = Ff(6m) = 2J Ff = 2J/6m = 1/3N

The Sun emits extremely large amounts of energy through solar flares. Which of the following reactions results from alpha decay? A. 214Pb -> 214Bi B. 222Rn -> 218At C. 210At -> 208Po D. 263Sg -> 259Rf

d) Alpha decay results in the ejection of an alpha particle from the nucleus. The alpha particle contains two protons and two neutrons. The two protons would decrease the atomic number by two and the total mass number of the atom would decrease by four. The only choice that satisfies both of these requirements is D, 263Sg -> 259Rf.

A person playing croquet on a grass lawn hits his yellow ball into his opponent's red ball. The friction coefficient between the ball and the lawn is approximately 0.25. Which of the following is true about the collision between the two balls? a. The collision is perfectly elastic, so the red ball and yellow ball will have the same kinetic energy after collision. b. The collision is inelastic, because some energy is absorbed by the friction between the balls and the grass. c. The collision is perfectly elastic, so the yellow ball will stop moving, and transfer all momentum to the red ball. d. The collision is inelastic, and the total kinetic energy in the system will be lower after the collision.

d) An elastic collision is one in which all of the kinetic energy is conserved in the collision. However, elastic collisions do not exist at large scale in the real world, and in this case the collision is not elastic. Instead, the collision is inelastic, meaning some kinetic energy is lost from the impact, usually as heat, sound, or vibration. The kinetic energy is lost as a result of the contact between the two balls, not because of the friction interaction between the grass and the ball, so answer B is not correct.

A student creates a 1M citrate (C3H5O(COO)33-) buffer solution at pH 5.0. He then dilutes the solution to 200 mM, and adds it to his experiment. What is the pH of the 200 mM buffer solution? A. Between pH 5 and pH 7 B. Greater than pH 7 C. Less than pH 5 D. The pH will remain close to 5

d) Buffers are designed to maintain pH at a certain level, and operate through the complementation of a conjugate acid and base. As long as the ratios of acid and base remain the same in the buffer system, and they will no matter what the dilution, as long as the dilution is not very very small (i.e. 1 mM or less), the pH will remain the same.

Which of the following molecules has the lowest vapor pressure? a) 2-propanone b) 2-butanone c) hexane d) 3-octanone

d) Having a low vapor pressure implies that the molecules have high intermolecular forces preventing them from evaporating. Two forces that we can look into are London dispersion forces and dipole-dipole. (a), (b), (d) have relatively similar dipole moments, and (c) has none, and we see that since (d) is larger than the other three, it has higher London dispersion forces than them. We see that (d) has the lowest vapor pressure because it has stronger London dispersion and dipole forces than the other molecules.

After sitting in a lecture, determining that a professor is a bad teacher based on their unprofessional attire and monotone speech is an example of which type of processing? a) Knowledge route processing b) Adaptive route processing c) Central route processing d) Peripheral route processing

d) Peripheral route processing deals with processing information that is not based on content, but instead on superficial parameters such as boring speech patterns or appearance of the speaker. Central route processing, choice (C), is the processing of information through analysis of its content.

A racecar travels in a circular path around the Daytona 500 track. The radius of the circular track is doubled and the speed of the car does not change. The required force to maintain the car's motion is: A. quadrupled. B. unchanged. C. doubled. D. halved.

d) The centripetal force of the car is mv2/r, where m is the car's mass, v is the velocity, and r is the radius of the circular track. If we double the radius while keeping everything else uniform, the centripetal force will be halved because they are inversely proportional.

When would it be appropriate to use extraction in order to separate compounds in a solution? a) When the compounds have differing molecular weights, but similar solubilities. b) When the compounds have similar molecular weights, but differing polarities. c) When the compounds have differing conjugated double bond lengths, but similar molecular weights. d) When the compounds have similar polarities, but differing solubilities.

d) extraction is a useful separation technique when there is a mixture of compounds in a solution that have similar polarities but different solubilities. The three-step process of extraction can take advantage of different solubilities by introducing the mixture to different acidic and basic conditions

A man of mass 75kg is riding a roller coaster, which has a total mass of 1000kg. As the ride enters a circular loop, it is traveling at a rate of 20ms. The loop has a radius of 5m. If the average frictional force on the coaster is 600N, how many g's of force does the man experience at the top of the loop? g=10ms2 a) 2.11g b) 0g c) 5.21g d) 3.65g e) 8.90g

d) to calculate g's we need to know the centripetal force the rider is experiencing. to calculate centripetal force, we need to know how fast the ride is traveling at the top of the loop., to do this, we will use the equation for conservation of energy: E = Ui + Ki = Uf + Kf + F If we set the height of the top of the loop to 10m, we can say that there is no initial potential energy. Since we are solving for final velocity, let's rearrange this for final kinetic energy: Kf = Ki - Uf - F Plugging in the expressions for each of these terms we get 1/2mv^2f = 1/2mv^2i - mghf - Ffd d = (pi)r = 5(pi) vf = 13.51 m/s now that we know how fast the ride is traveling at the top of the loop, we can calculate the centripetal force on the man: Fc = mac = mv^2/r = 2737 N Now that we know the force in Newtons, we can convert this value to g's. For this man: 1'g' = mg = 750 N therefore G = 2737N/750N/g = 3.65g

All of the following require ATP to function, except __________. a) motility of mature sperm cells b) polarization during action potentials in axons c) synthesis of macromolecules d) transport of non-permeable solutes down their concentration gradients

d) while non-permeable solutes require a carrier protein to allow passage into a cell, they do not require ATP or energy if they are traveling down their concentration gradient; energy is only required if they are traveling against their gradient

Pulmonary alveolus (plural form:alveoli) is an integral component of the mammalian respiratory system, which of the following characteristics describes this component? a) Actively transports O2 into the bloodstream b) Allows for gas diffusion to occur and the exchange of CO2 for O2 in the bloodstream c) Hollow cavities at the end of the respiratory tree d) B and C

d) Alveoli are found in the parenchyma of the lungs at the terminal end of the respiratory tree. Alveoli in the lungs of mammals are the key structure in facilitating the exchange of CO2 and O2 across the alveolar membrane by pumping CO2 rich blood from the body into the oxygen rich alveoli and allowing the exchange to occur through diffusion, not active transport.

The 1H-NMR spectrum of an organic molecule returns as a single peak. Which of the following could NOT be the molecule in question? a) methane b) ethane c) propadiene d) 2-methylpropane

d) Answers (A), (B), and (C) each have equivalent hydrogen atoms that are indistinguishable from one another. The 4 hydrogen atoms of methane are identical; the two sets of methyl groups comprising ethane are identical; the two =CH2 groups of propadiene are also identical. Only 2-methylpropane has non-equivalent hydrogen atoms because it has a -CH group as well as 3 methyl groups which would result in multiple peaks being shown on the NMR spectrum.

Consider a biochemical reaction A → B, which is catalyzed by A-B dehydrogenase. Which of the following statements is true? a) The reaction will proceed until the enzyme concentration decreases. b) The reaction will be most favorable at 0 °C. c) A component of the enzyme is transferred from A to B. d) The free energy change (ΔG) of the catalyzed reaction is the same as for the uncatalyzed reaction.

d) Enzymes catalyze reactions by lowering their activation energy, and are not changed or consumed during the course of the reaction. While the activation energy is lowered, the free energy of the reaction, ΔG, remains unchanged in the presence of an enzyme. A reaction will continue to occur in the presence or absence of an enzyme; it simply runs slower without the enzyme, eliminating choice (A). Most physiological reactions are optimized at body temperature, 37 °C, eliminating choice (B). Finally, dehydrogenases catalyze oxidation-reduction reactions, not transfer reactions, eliminating choice (C).

The density of an unknown gas under STP conditions is 3.17 g.L-1. What is the molecular mass of the gas? A. 3.17/24.5 = 0.13 B. 3.17/22.4 = 0.14 C. 3.17 x 24.5 = 77.7 D. 3.17 x 22.4 = 71.0

d) STP is Standard Temperature and Pressure or 0oC and 1 atm pressure. At STP 1 mole of an ideal gas occupies 22.4 L. A good approximation of the molecular mass of a gas is obtained by multiplying its density in g.L-1 by 22.4 L to attain the mass of 1 mole of gas. Hence: 3.17 x 22.4 = 71.0 24.5 L is the molar volume of an ideal gas under LTP or Laboratory Temperature and Pressure, a balmy 25oC and 1 atm pressure.

Which of the following compounds would be expected to have the least amount of steric strain on its bonds? a) cyclopropane b) cyclobutane c) cyclopentane d) cyclohexane

d) Steric strain is a result of bond angles that are forced against their optimal conformation (based on the van der Waals repulsion of substituent groups). sp3-hybridized carbon atoms have bond angles of 109.5� which is optimal; cyclopropane would have bond angles of 60� while cyclohexane would have angles of 120� which are much closer to optimal. Thus cyclohexane would have the least steric strain.

A molecule with square planar geometry, like XeF4 has different geometry from SiCl4 because: a) Xe is an inert gas. b) Fluorine is more electronegative than Xenon. c) The bond angles for the square planar geometry are larger than for the tetrahedral geometry, making XeF4 more stable as a square planar molecule. d) XeF4 has two lone pairs in addition to the four bonds.

d) While (A) is true, it does not explain the observation discussed, making it an incorrect answer. (B) is also true but the electronegativity of elements does not greatly impact their molecular geometry. (C) is incorrect because the bond angles for SiCl4 (109.5°) are actually greater than for square planar molecules (90°). The answer is (D) because while Si in SiCl4 has no lone pairs, Xe in XeF4 does. The resulting electron repulsion forms a square planar geometry.

Hydrogen gas generated in a reaction is collected over water at 25 degrees Celsius and is found to have a pressure of 746 torr. The vapor pressure of water at 25 degrees Celsius is 24 torr. Which expression can be used to find the pressure of H2, in atm? A. 24/760 B. 746/760 C. (746 + 24)/760 D. (746 - 24)/760

d) You must subtract the pressure of water vapor from the total pressure, and change torr to atm. 1 atm = 760 torr = 760 mm Hg.

Suppose that a social movement takes place in vocational training schools. Although everyone attending vocational school is affected, the changes to daily life are relatively small. How would this social movement be classified? a) Redemptive b) Alternative c) Revolutionary d) Reformative

d) a reformative social movement affects everyone in a group, but has limited change. Alternative social movements affect a small percentage of a group and have a small impact. Redemptive movements affect a small percentage of a group, but in a radical way. Revolutionary movements affect a whole group in a radical way

Which set of 1 Molar solutions has the correct pH values? A. Water pH = 0; hydrochloric acid pH = 4; acetic acid pH = 7; ammonia solution pH = 10; sodium hydroxide solution pH = 14. B. Acetic acid pH = 0; hydrochloric acid pH = 4; water pH = 7; sodium hydroxide solution pH = 10; ammonia solution pH = 14. C. Sodium hydroxide solution pH = 0; ammonia solution pH = 4; water pH = 7; acetic acid pH = 10; hydrochloric acid pH = 14. D. Hydrochloric acid pH = 0; acetic acid pH = 4; water pH = 7; ammonia solution pH = 10; sodium hydroxide solution pH = 14.

d)Acids have pH values of less than 7, with the stronger the acid the lower the pH. Bases have pH values of greater than 7, with the stronger the base the higher the pH. Typically: Strong acids have a pH of 0 or less, hydrochloric acid pH = 0. Weak acids between pH 3-6, acetic acid pH = 4. Neutral solutions have pH = 7, water pH = 7. Weak bases have a pH 8-10, ammonia solution pH = 10. Strong bases have a pH of 14 or more, sodium hydroxide solution pH = 14.

While most of the hormones in the anterior pituitary require a factor from the hypothalamus to be released, prolactin defies this rule. As long as the hypothalamus continues to release prolactin inhibitory factor, no prolactin will be generated. The absence of prolactin inhibitory factor releases this block. Which of the following incorrectly pairs a hypothalamus hormone with its anterior pituitary hormone secreted in response? A. Gonadotropin-releasing hormone -> follicle-stimulating hormone (FSH) and luteinizing hormone (LH) B. Growth hormone-releasing hormone (GHRH) ->growth hormone (GH) C. Thyroid-releasing hormone (TRH) -> thyroid-stimulating hormone (TSH) D. Corticotropin-releasing factor (CRF) ->adrenocorticotropic hormone (ACTH) E. None of the above

e) A-D are actually correct. Let's go through them. The release of CRF leads to the secretion of ACTH, which then causes the adrenal cortex to increase the level of cortisol secreted into the bloodstream. FSH and LH act on the gonads (testes and ovaries). It is not surprising that TSH acts on the thyroid. Growth hormone is also true to its name, promoting the growth of bone and muscle. It does so by preventing the uptake of glucose in certain tissues and stimulating the breakdown of fatty acid, also increasing the presence of glucose available for bone and muscle to use.

Imagine that a toxin is introduced to the body and inhibits the establishment of the proton gradient in the intermembrane space. What would you predict would be the result? a) Fermentation could not occur b) Pyruvate would be unable to enter the Krebs cycle c) NADH would be oxidized d) Substrate-level phosphorylation would be inhibited e) ATP synthase would be unable to produce ATP

e) ATP synthase is dependent on a proton gradient in the intermembrane space in order to produce ATP. As a result, the toxin will make it inactive. Oxidative phosphorylation would be inhibited in this case, as opposed to substrate-level phosphorylation. Pyruvate is a product of glycolysis, and would not be affected by the toxin. NADH is key in the establishment of the proton gradient, so we would expect that it would be unable to be oxidized due to the toxin. Protons produced in the conversion of NADH to NAD+ (+H^+) establish the proton gradient. If the gradient is absent, NADH is likely not be oxidized

: In the 1950s, science and engineering melded with the production of computers and artificial intelligence. The model of information processing applied to these fields gave rise to the same analysis of the human brain, with the hypothesis that it functioned like a computer. Which of the following is not a key component of the information processing model? A. Thinking requires sensation, encoding, and storage of stimuli B. Stimuli must be analyzed by the brain (rather than responded to automatically) to be helpful in decision making C. Decisions made in one situation can be modified for new situations D. Problem solving is dependent not only on cognitive level, but also context and complexity of the problem E. None of the above

e) Although it was hypothesized that the human brain functioned like a computer, this ultimately does not tell the full story. The brain does not just handle facts, but also emotions, sensations like smell and taste, and memories. A through D outline the four key components of the information processing model, making E the correct answer.

If the first overtone of a sound wave in a pipe with one end open and one end closed has a frequency of 300Hz, what is the frequency of the second overtone? a) 600Hz b) 450Hz c) 150Hz d) 500Hz e) 200Hz

e) In an open-closed pipe, we get only odd harmonics, since there must always be a displacement node at the closed end and a displacement antinode at the open end. So, the first overtone is the same as the third harmonic, which has F3 = 3F1. Similarly, the second overtone is the fifth harmonic, which has F5 = 5f1. Using the given values of f3 in the first overtone to be 300 Hz, we find f1 = 100Hz and f5 = 500 Hz

During replication, the parental strands of DNA serve as templates for the generation of new daughter strands. This is coined a semiconservative process since one parental strand is retained in the resulting identical double stranded DNA molecules. Which of the following mismatches a protein with its function? A. Nucleases degrade DNA B. DNA gyrase is a DNA topoisomerase II C. DNA polymerase I removes RNA in prokaryotes D. DNA ligase seals the ends of DNA molecules together E. Single-stranded DNA-binding proteins stabilize double stranded DNA

e) Nucleases do degrade DNA, which is why single-stranded DNA-binding proteins bind the unraveling strand. They prevent both the association of the single strands into double strands, as well as the degradation by nucleases. This eliminates A. It also points out that E is the correct answer. Single-stranded DNA-binding proteins do not stabilize double stranded DNA, they stabilize single stranded DNA. B through D are therefore eliminated too.

The human genome has roughly 3 billion base pairs packaged into multiple chromosomes. The replication complex is the set of specialized proteins that assists the DNA polymerases. Which of the following distinguishes between the bacterial and eukaryotic chromosomes? A. The bacterial chromosome is linear, while the eukaryotic is circular B. The bacterial chromosome is double stranded, while the eukaryotic is single stranded C. The bacterial chromosome has multiple points of replication, while the eukaryotic has a single point of replication D. Bacterial replication is slower than eukaryotic replication E. None of the above

e) The bacterial chromosome is closed, double stranded, and circular, while the eukaryotic chromosome is a linear molecule of double stranded DNA. This means that A and B are reversed. The bacterial chromosome has a single point of replication, versus the multiple points of replication for the eukaryotic chromosome. This eliminates C. Given that the bacterial genome is smaller than the eukaryotic genome, it will be faster to replicate it. This eliminates D. Ultimately, E is correct.

For the transfer of heat between two objects to occur, they must be in thermal contact with each other. This does not mean that they are necessarily touching, because energy can travel tremendous distances since it does not require a medium through which to pass. Which of the following correctly describes the following three heat transfer processes? I. A metal spoon heating up when placed in hot soup II. A rising plume of smoke from a fire III. Heat transferred from the Sun to the Earth A. I. Radiation; II. Conduction; III. Convection B. I. Conduction; II. Radiation; III. Convection C. I. Radiation; II. Convection; III. Conduction D. I. Convection; II. Conduction; III. Radiation E. None of the above

e) The empty space between the Sun and the Earth means heat transfer can occur only by radiation (electromagnetic waves propagate across space). When the metal spoon is placed in hot soup, the molecules in the soup collide with those on the surface of the spoon, since they are in contact, resulting in heat transfer by conduction. Last, fire warms the air above it, making it less dense than the surrounding air and able to rise. This rising column of warm air means heat is transported in the air mass, which is the process of convection. The smoke particles hitch a ride and create the plum. Ultimately, only E matches this.

The thyroid, controlled by thyroid stimulating hormone, which comes from the anterior pituitary, is located on the front of the trachea. Clinically, it can be palpated as the organ near the base of the neck, which moves up and down with swallowing. Which of the following is not a thyroid function? A. Iodination of tyrosine in follicular cells B. Modulation of energy production efficiency C. Modulation of cellular respiration D. Control of protein and fatty acid turnover E. None of the above

e) The thyroid has two major purposes: to set the basal metabolic rate and second, calcium homeostasis. The first is done via triiodothyronine (T3) and thyroxine (T4), while calcium levels are controlled via calcitonin. A is absolutely true and accounts for the production of T3 and T4. The numbers three and four actually refer to the number of iodine atoms attached. Therefore, A is true (making it incorrect). The basal metabolic rate is set by modulating energy production efficiency, ruling out B. Increased T3 and T4 leads to increased cellular respiration, leading to greater turnover of proteins and fatty acids due to increased synthesis and degradation of said compounds. This makes C and D incorrect as well.

Which of the following does NOT perform endocrine function? a) Thyroid b) Pancreas c) Testes d) Liver e) All of these are endocrine organs

e) endocrine organs are capable of secreting hormones into the bloodstream. Each of the given answer options perform some sort of endocrine function the testes secrete testosterone, and are responsible for the development of most secondary sex characteristics in males the thyroid gland secretes calcitonin and thyroid hormones, responsible for elevating calcium levels and increasing metabolism, respectively the pancreas and liver are both endocrine AND exocrine organs. As an endocrine organ, the pancreas secretes the hormones insulin and glucagon. As an exocrine organ, it secretes several enzymes that are essential for digestion in the small intestine. The liver secretes insulin-like growth factors in response to stimulation by growth hormone. As an exocrine organ, it is also responsible for producing bile to aid in digestion

A scientist is studying a reaction, and places the reactants in a beaker at room temperature. The reaction progresses, and she analyzes the products via NMR. Based on the NMR readout, she determines the reaction proceeds as follows: NH+4(aq)+NO−2(aq)→N2(g)+2H2O(l) In an attempt to better understand the reaction process, she varies the concentrations of the reactants and studies how the rate of the reaction changes. The table below shows the reaction concentrations as she makes modifications in three experimental trials. Trial [NH+4] [NO−2] Rate 1 0.480M 0.120M 0.018M/s 2 0.240M 0.120M 0.009M/s 3 0.240M 0.360M 0.027M/s The scientist in the passage calculates that, under experimental conditions, the given reaction releases 150J/mol before it comes to equilibrium. Under the exact same conditions, another unknown reaction is studied. This second reaction releases 15000J/mol before it comes to equilibrium. Which of the following must be true? a) The first reaction will progress faster at the experimental conditions, but may be slower at other conditions b) the second reaction will progress faster at the experimental conditions, but may be slower at other conditions c) the first reaction will always progress faster d) the second reaction will always progress faster e) We cannot predict the relative rates of these two reactions with the information given

e) the amount of energy released or absorbed by a reaction is independent of its rate. Rate is principally determined by the activation energy, while the inherent bond energies of reactants and products dictate thermodynamic changes. One cannot be used to predict the other

Members of a species of red fox have teeth of varying sharpness. Foxes with very sharp teeth are able to kill large prey for food, while foxes with very dull, strong teeth are able to crush eggs and small animals. Foxes with teeth of medium sharpness, however, cannot get food and many die before they are able to reproduce. Over time, the fox population shows a greater proportion of individuals with either very sharp or very dull teeth. Which type of natural selection best describes this situation? a) Directional selection b) Artificial selection c) Stabilizing selection d) Vestigial selection e) Disruptive selection

e) In this scenario, the two extreme phenotypes are selected for, wile intermediate phenotypes are selected against. This is disruptive natural selection. Over time, disruptive selection results in a decreased frequency of "middle" phenotypes and an increased frequency of the two groups at the extreme ends. This is a process that can eventually lead to speciation. The opposite is process stabilizing selection, in which the extreme variations are selected against in favor of more "average" phenotypes. Directional selection occurs when only one end of the spectrum is favored, such as sharp teeth but not dull teeth. Artificial selection involves human intervention in selecting desirable traits. Vestigial selection is not a type of natural selection

Sarin gas is a potent nerve agent that quickly causes serious physiological effects if ingested, even in very small quantities. It inhibits acetylcholinesterase, an enzyme that degrades acetylcholine. Acetylcholinesterase generally acts at the neuromuscular junction. Sarin gas may cause which of the following? a) Inhibition of peristalsis b) Reduced blood pH (acidosis) c) Dilated pupils d) Increased production of white blood cells e) Loss of control of respiratory muscles

e) acetylcholine is the neurotransmitter that acts at neuromuscular junctions. Acetylcholinesterase degrades acetylcholine at the synaptic cleft, allowing the muscle to relax. If acetylcholinesterase is inhibited, acetylcholine will remain in the synaptic cleft and continueously stimulate the muscle. reathing requires the ability to contract and relax respiratory muscles. Without rapid administration of an antidote, sarin gas usually results in death from asphyxiation. Acetylcholine causes pupil constriction and gastrointestinal motility. it is not associated with a rapid increase in leukocyte production

Which of the following is not true of hydrogen bonds? a) They are stronger than van der Waals interactions b) They are weak bonds that are easily formed and broken c) They may occur between different molecules or within a single molecule d) They explain many of the properties of water e) They can form between molecules with either polar or nonpolar covalent bonds

e) hydrogen bonds are only formed between molecules with polar covalent bonds, and not in nonpolar molecules. They result from the electromagnetic attraction between hydrogen (which is slightly positively charged) and an atom of opposite (negative) charge, namely the negative charged end of a polar molecule. All the other statements are accurate

Liquids experience thermal expansion, but it is more practical to measure it in terms of volume expansion. In fact, the formula for volumetric expansion can be applied to both liquids and solids. Which of the following is not true regarding volumetric expansion? A. It is proportional to the original volume B. It is proportional to the change in temperature C. It is proportional to three times the coefficient of linear expansion D. It is not proportional to the length E. None of the above

e) The equation for volumetric expansion is: ΔV=βVΔT β-coefficient of volumetric expansion (which is equal to three times the coefficient of linear expansion) V-original volume ΔT-change in temperature As you can see, statements A through D hold true, making E correct.

A patient is recovering from a bacterial toxin that has damaged a large majority of the microvilli in their small intestine. Which is the most immediate issue they should be concerned about? a) Enzyme secretion b) Structure and support of the intestine c) Blood loss d) Mechanical digestion e) Nutrient absorption

e) the patient should be most concerned with nutrient absorption. Microvilli provide additional surface area to the small intestine, allowing for nutrient absorption. If the lining of the intestine were completely smooth, nutrients would pass too quickly through the digestive system. Enzyme secretion is primarily provided by the liver and pancrease