DAT Practice Problems
What are sigma bonds?
-single covalent bonds -overlap of two orbitals directly between the bonding atoms.
1) A 2) B 3) C
2) B
1) A 2) B 3) C 4) D 5) E
3) C
1) A 2) B 3) C 4) D 5) E
4) D
Which of the following is a major distinction between veins and arteries? A) veins have valves B) arteries carry blood to the heart C) veins carry blood away from the heart D) arteries have thinner cell walls. E) veins are under high pressure.
A) veins have valves Veins carry blood to the heart, recollecting it from the body. Conversely, arteries carry blood away from the heart to the body. To prevent backflow and to promote the movement against gravity, veins have valves whereas arteries do not. Arteries also have very thick, muscular walls that enable pumping from the heart to the body. Veins are thinner in comparison and are not considered to have to "pump" blood or be under high pressure.
Mark's car began a journey from a point at 7 AM, traveling at 30 mph. At 8 AM Jason's car started traveling from the same point at 40 mph in the same direction as Jason. At what time will Jason pass Mark? A. 10 AM. B. 11 AM. C. 10:30 AM. D. 11:30 AM. E. Jason never passes Mark.
A. 10 AM.
In how many different ways can the first, second and third prize winners be selected from a group of 8 people running a race? [assume that there are no ties]. A. 8! / 5! B. 8! / (5! × 3!) C. 8! D. 38 E. 8! / (5! × 3)
A. 8! / 5!
The cyanide ion has which of the following molecular geometries? A. Linear B. Trigonal Planar C. Tetrahedral D. Trigonal Planar-Bent E. Tetrahedral-Bent
A. Linear A cyanide is a chemical compound that contains the group C≡N. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom.In inorganic cyanides, the cyanide group is present as the anion CN−.
A deuterostome embryo would exhibit which type of cleavage? A. radial B. spiral C. central D. bilateral E. lateral
A. radial Spiral cleavage results in daughter cells after cell division, being located at an angle in relationship to each other. This is common in protostomes. Whereas radial cleavage results in the daughter cells after cell division being stacked on top of each other. Radial cleavage is seen in deuterostomes.
John, Jack and Jason share an amount in the ratio of 4:3:7, respectively. If Jason received $32 more than Jack, what is the total amount they shared? A) $64 B) $112 C) $148 D) $172 E) $96
B) $112 Since the ratio is 4:3:7, we can assume that the amounts received by John, Jack and Jason are 4x,3x and 7x, rescpectively. Since Jason received $32 more than Jack,
A rectangular tank 82 cm long, 37 cm wide and 75 cm deep has the same volume as a cylindrical tank. If the radius of the cylindrical tank is 30 cm, what is its height (in cm) ? [let π = 3.14] A. 83 B. 80.52 C. 52.8 D. 50.8 E. 62.5
B. 80.52
Which of the following is sometimes referred "programmed cell death" because it leads to an organized destruction of the cell? A. Cellular senescence B. Apoptosis C. Necrosis D. Immortalization E. Telophase
B. Apoptosis
Mixture A is formed using KCl and H₂O and mixture B is formed using MgCl₂ and H₂O. If the two mixtures have the same molality, which of the following statements would be true about the boiling point of the mixtures? A. Mixture A would have a higher boiling point B. Mixture A would have a lower boiling point C. Mixture B would have a lower boiling point D. The mixtures have the same boiling point E. The mixtures would vaporize at the same rate
B. Mixture A would have a lower boiling point
What reagent can be used to convert 2,2-dimethylbutan-1-ol into 2,2-dimethylbutanal? A. H₂CrO B. PCC C. KMnO₄ D. O3 E. LiAlH₄
B. PCC The conversion of 2,2-dimethylbutan-1-ol to 2,2-dimethylbutanal is an oxidation (alcohol -> aldehyde). Lithium aluminum hydride (E) is a strong reducing agent. Potassium permanganate (C) is used in the oxidation of alkenes to diols, and is generally not strong enough to further oxidize aliphatic alcohols. Ozone (D) is used in the oxidative cleavage of alkenes into the corresponding aldehydes or ketones. Chromic acid (A) is a harsh oxidant, oxidizing primary alcohols up to the corresponding carboxylic acid, and secondary alcohols up to the corresponding ketone. PCC (B, pyridinium chlorochromate) is a milder chromium-based oxidant used in the selective oxidation of primary alcohols to aldehydes.
What is the final oxidation number of carbon in the following chemical reaction? 6CO2 + 6H2O ---> C6H12O6 + 6O2 A. -4 B. -2 C. 0 D. 2 E. 4
C) 0 In the equation, carbon is used from carbon dioxide to form glucose, C6H12O6. The final form of carbon is in glucose. In this compound, the oxygens each have an oxidation number of -2 and the hydrogen also have a fixed oxidation number of +1 each. Therefore, the sum of hydrogen's oxidation numbers is +12 and the sum of oxygen's oxidation numbers is -12. Since glucose is a neutral compound the sum of all the oxidation numbers of all the elements in the compound must be equal to zero. So, carbon must have an oxidation number of 0 because the sum of the hydrogen and oxygen oxidation numbers is already equal to zero.
A 1 mol sample of ammonia gas (NH3) at 1 atm and 273 K is compressed to 2 atm. What is the difference in volume before and after compression? A) 22.4 liters B) 18.5 liters C) 11.2 liters D) 5.91 liters E) 1 liter
C) 11.2 liters This is solved using the ideal gas law. However, it should be recognized that 1 mol of any gas at 1 atm and 273K (or 0 deg Celsius) is approximately 22.4 L in volume. If this is not recognized, it can still be calculated from the ideal gas law, PV = nRT. We recognize that if pressure doubles while temperature and mols remain the same, the volume should be halved. Thus, the new volume is 11.2 L, which is a difference of 11.2 liters, or answer C.
Which of the following statements is correct? A) High molecular dipole moments are characteristic of nonpolar molecules B) Polar solutes tend to be more soluble in nonpolar solvents C) The polarity of a molecule is dependent on its 3-D structure D) All polar molecules are capable of hydrogen bonding E) London dispersion interactions are usually stronger than dipole-dipole interactions
C) The polarity of a molecule is dependent on its 3-D structure A molecule's dipole is an electric dipole with an inherent electric field (not be confused with a magnetic dipole which generates a magnetic field). Molecules can have dipole moments due to non-uniform distributions of positive and negative charges on the various atoms. For diatomic molecules there is only one (single or multiple) bond so the bond dipole moment is the molecular dipole moment, with typical values in the range of 0 to 11 D. For polyatomic molecules there is more than one bond, and the total molecular dipole moment may be approximated as the vector sum of all individual bond dipole moments.
A car starts from a static position and accelerates uniformly until it reaches a certain speed. If five cars reach the following speeds in the given amounts of time, which car will have gone the farthest distance after 1 second? A. 0 to 60 mph in 4 seconds B. 0 to 75 mph in 5 seconds C. 0 to 55 mph in 3.5 seconds D. 0 to 45 mph in 3 seconds E. 0 to 65 mph in 4.5 seconds
C. 0 to 55 mph in 3.5 seconds A uniform acceleration implies that the speed increases linearly. So, at the end of the first second, the speed for the first car will be simply 60 / 4 = 15 mph, which is the same for the answer choices B and D as well. The speed after 1 sec for choice C is higher than 15 mph, and that for E is lower than 15 mph. So, the car in C has the highest speed after 1 sec. Since its average speed over this 1 sec period is higher than the rest of the cars, it must have traveled more distance than the others during this period as well.
An Olympic gold medalist runs 100 meters in 9.7 seconds. What is his average speed in miles per hour? A. 17 B. 8 C. 23 D. 28 E. 11
C. 23
Two trains are approaching each other from opposite directions with the speeds 10 miles per hour and 20 miles per hour, and heading for a collision. If they are a quarter mile apart, how long will it take for them to collide? A. 45 seconds B. 20 seconds C. 30 seconds D. 40 seconds E. 1 minute
C. 30 seconds The speed at which the two trains are closing the gap between them is 10 + 20 = 30 mph. At the is speed, it will take (0.25/30) × 3600 = 30 seconds to close a gap of 0.25 miles.
From a group of 5 men and 7 women, in how many different ways can a team of 2 men and 3 women be formed? A. 95040 B. 792 C. 350 D. 4200 E. 18
C. 350 2 men can be picked from a group of 5 in (5|2) = 10 different ways, and 3 women can be picked from a group of 7 in (7|3) = 35 different ways. Therefore, the total number of ways a team can be formed is 10 × 35 = 350. Extended explanation: If you got D. 4200, you interpreted this problem as a permutation, not as a combination. We do not care what order the men are picked in or what order the women are picked in, all we care is that there is a team of 2 men and a team of 3 women.
There are 5 white, 7 red and 8 black balls in a box. If you are blindly picking up balls from the box, what is the minimum number of balls you need to take out of the box to ensure that you have at least 2 balls of the same color? A. 2. B. 3. C. 4. D. 5. E. 6.
C. 4. because you are randomly selecting from 20 balls; 5 white, 7 red and 8 black. if you only select 3 balls there is a chance you will get 3 different color balls and we're trying to find the minimum number we can get to ensure 2 of the same color. so 4 would be the right answer because no matter what color combinations you get you will always get 2 of at least one color every time.
Which of the following will not dissolve in water? A. Salt, NaCl B. Ethanol, CH3CH2OH C. Benzene, C6H6 D. Hydrogen chloride, HCl E. Acetic acid, CH3COOH
C. Benzene, C6H6
Which of the following hormones is responsible for the thickening of the endometrium? A. Testosterone B. Oxytocin C. Estrogen D. Luteinizing hormone E. Follicle stimulating hormone
C. Estrogen Follicle stimulating hormone causes the follicle in the ovary to begin to divide to complete meiosis II. The growing follicle that will eventually release the egg during ovulation secretes estrogen. The estrogen then spurs the secretion of luteinizing hormone by the anterior pituitary gland, causing the follicle to rupture and release the egg. It is the estrogen and progesterone that is responsible for readying the endometrium for implantation should fertilization occur.
What is the major product of the following reaction? A. I B. II C. III D. IV E. The reaction produces mixtures of all four.
C. III The bromonium ion is formed when alkenes react with bromine. When the π cloud of the alkene (nucleophile) approaches the bromine molecule (acting as an electrophile), the σ-bond electrons of Br2 are pushed away, resulting in the departure of the bromide anion. The species formed is a high-energy intermediate along the reaction path. It will react further with some nucleophile−methanol in this case. The electronic structure of the bromonium ion has its consequences in the stereochemistry of the reaction. Nucleophilic attack takes place from the bottom face (back-side to the "departing" bromide) on the more substituted carbon. The back-side attack leads to the anti addition (Br and Nu groups end up on the opposite faces of the starting double bond), and the nucleophile adds to the more substituted carbon (Markovnikov's rule). Structure III corresponds to the above. Structure II may form, but only in very miniscule amounts.
For a mixture of gases in a container, the total pressure is equal to __________ because of what law? A. The pressure of the largest gas, First Law of Thermodynamics. B. The pressure of the smallest gas, First Law of thermodynamics. C. The sum of the partial pressures of all gases, Dalton's law of partial pressure. D. The pressure of the greatest gas, Dalton's law. E. The sum of the top two gases in the mixture, Dalton's law of partial pressure.
C. The sum of the partial pressures of all gases, Dalton's law of partial pressure.
As urine moves through the descending loop of Henle, which of the following is true? A. Sodium is reabsorbed into the bloodstream. B. Sodium is secreted into the loop of Henle. C. Water is reabsorbed into the bloodstream. D. Water is secreted into the loop of Henle. E. Potassium is reabsorbed into the bloodstream.
C. Water is reabsorbed into the bloodstream. The descending loop of Henle is only permeable to water. As the urine moves through the loop of Henle, it will become more concentrated as the water is reabsorbed back into the bloodstream. The ascending loop of Henle is permeable to sodium and during this portion of the loop, the urine will be come more diluted, as sodium ions are reabsorbed into the bloodstream.
In cattle, black hair color is dominant to red hair color. Which of the following would a farmer use to mate with a black haired cow to determine the black cow's genotype? A. a homozygous black haired cow B. a heterozygous black haired cow C. a homozygous red haired cow D. a heterozygous white cow E. a homozygous albino cow
C. a homozygous red haired cow need a homozygous recessive
How many degrees of unsaturation are present in the anxiolytic drug Valium (diazepam), molecular formula (C16)(H13)(Cl)(N2)(O)? A. 8 B. 9 C. 10 D. 11 E. 12
D. 11 Degree of Unsaturation (or index of hydrogen deficiency, IHD), or rings plus pi bonds, lets you determine the number of rings, double bonds and triple bonds present in the compound if the molecular formul is known. It does not give the exact number of rings or double or triple bonds, but rather the sum of the number of rings and double bonds plus twice the number of triple bonds. Degree of Unsaturation = C - (H/2) - (X/2) + (N/2) +1 (C=#carbon, H=#hydrogen, X=#halogen, N=#nitrogen) = 16 - (13/2) - (1/2) + (2/2) + 1 = 11
It takes 6 minutes and 12 minutes, respectively, to run two computer programs when they are run one at a time. However, their speeds are reduced by 50% and 40%, respectively, if running in parallel. If a PC starts running the two programs together, how long will it take for them to finish? A. 17.4 minutes B. 18 minutes C. 16 minutes D. 16.8 minutes E. 15.5 minutes
D. 16.8 minutes 40% of 12 minutes is 4.8 minutes, so you add 12 and 4.8 which is 16.8. this program will take longer than the other one which will take 9 mins at reduced speed so the answer is 16.8
If an unknown compound is found to have an empirical formula of CH4, which of the following is the molecular formula if the molar mass was determined to be 128 g/mol? A. CH4 B. CH12 C. C8H12 D. C8H32 E. C12H16
D. C8H32 To determine the molecular formula using an empirical formula, the ratio of the molecular mass to the empirical mass must be calculated. Dividing the molecular mass of 128 grams by the empirical mass of ~16 grams (C = 12g + H = 1g, but there are 4 hydrogens in the compound) gives you approximately 8. This indicates that the empirical subscripts must be multiplied by 8 to result in the molecular formula of the unknown compound, C8H32.
Which of the following structures is responsible for the release of calcium ions? A. Neuron B. Sarcomere C. Intercalated disks D. Sarcoplasmic reticulum E. Endoplasmic reticulum
D. Sarcoplasmic reticulum Calcium ions are essential for muscle contraction to occur. Without the release of calcium, the myosin head would be unable to bind to the actin at the binding sites. It is the calcium that binds and removes troponin from the myosin binding sites on the actin. This is done when the axon terminal nearest a muscle fiber releases acetylcholine, a neurotransmitter, which then causes the sarcoplasmic reticulum to release calcium into the muscle cell to allow for muscle contraction. The endoplasmic reticulum is responsible for protein modification following translation on a ribosome.
Which of the following is the specialized structure on the sperm that contains hydrolytic enzymes? A. flagella B. plasmid C. capsid D. acrosome E. sperm tail
D. acrosome The head of the sperm contains the acrosome, which has specialized enzymes that when released, help the sperm to penetrate and fertilize the egg. A plasmid is a small bacterium that can be used in recombinant DNA formation. The capsid is the protein coat that encapsulates a virus' genetic material. The flagella are important for motility of the sperm but do not contain any enzymes.
A friend of yours draws a circle circumscribing a regular octagon. What is the ratio of the area of the octagon to the circle? A. π. B. √2/2. C. (π√2)/4. D. √2/(2π). E. (2√2)/π.
E. (2√2)/π.
If 45.1 grams of a solute is added to 302 grams of water to make a 0.65M solution, what is the molar mass of a solute? A. (45.1 grams)/(0.302 moles) B. (0.65(.302) grams)/(45.1 moles) C. (45.1 grams)/(0.65 moles) D. (0.65 grams)/(0.302 moles) E. (45.1 grams)/(0.65(.302) moles)
E. (45.1 grams)/(0.65(.302) moles)
A seller gives a 10% discount to a customer who pays cash. What is the marked price of an item for which the customer pays $225? A. 275 B. 235 C. 200 D. 247.50 E. 250
E. 250
Which of the following structures of the skeletal system is innervated? A. Hair B. Nails C. Cartilage D. Osteoclasts E. Haversian canals
E. Haversian canals Innervated refers to the structure having nerves and blood vessels that run through it. Nails and hair are consider dead/dying cells and would not have blood vessels that run through the exterior nail structure. Cartilage is not innervated which attributes to the long healing time of sprained joints. Osteoclasts are cells that help to break down bone cells and these cells themselves do not have blood vessels or nerves. The Haversian canals are a network of opening in the bone that allow for nerves and blood vessels to weave in and out of the bone.
Which of the radioactive decay particles have the lowest penetrating power? A. proton B. positron C. gamma rays D. beta particles E. alpha particles
E. alpha particles In order of increasing penetration power, alpha particles have the lowest, then beta particles, then gamma rays. Protons are not known to have penetrating power and a positron is generally unstable and quickly decomposes, so its penetrating power is considered to be negligible.
Which of the following molecules is amphipathic? A. water B. glucose C. steroids D. triglycerides E. phospholipids
E. phospholipids An amphipathic molecule has both a hydrophilic ("water loving") and a hydrophobic ("water fearing") region. Water is hydrophilic, whereas a triglyceride (or lipid) is hydrophobic. Glucose is also hydrophilic. Steroids are derived from lipids and also would be hydrophobic. A phospholipid is made of a phosphate group (hydrophilic) and two fatty acid chains (hydrophobic) and is amphipathic.
What is the ideal gas law?
PV=nRT
What is a deuterostome?
Type of coelmate whose anus develops before the mouth
Which of the following equals the value of cos(π/3)? a) -cos(2π/3) b) cos (2π/3) c) cos (6π/3) d) -cos(5π/3) e) cos (4π/3)
a) -cos(2π/3) because cos(π/3) = -cos(2π/3)= 1/2
Which among the following does not exhibit geometric isomerism? a) 1-hexane b) 2-hexene c) 3-hexene d) 4-hexene e) none of the above
a) 1-hexane Alkenes like 1-hexene when flipped from top to bottom they have identical structures and also they have C=CH2 unit which does not exist as cis- trans isomers
A researcher is attempting to predict the number of lions in an African habitat based on previous data. He has formed a regression equation which is Y=25 + 0.5X-2ZX, where X is the number of years since the first population sample, and Z is the death rate of the lions. If it has been 10 years, and the death rate is 1 lion per year, what is the predicted number of lions in the habitat? a) 10 b) 12 c) 16 d) 18 e) 20
a) 10
An unknown metal of 50g is initially at 100 degrees celsius and dropped into a beaker of 200g of water at 30 degrees celsius. The final temperature of the system is 40 degrees celsius. Find the specific heat of the metal if the specific heat of water is 4.2 J/g degrees celsius. a) 2.8 J/g degrees celsius. b) 4.2 J/g degrees celsius. c) 5.1 J/g degrees celsius. d) 6.4 J/g degrees celsius. e) 10 J/g degrees celsius.
a) 2.8 J/g degrees celsius. Heat lost by metal = heat gained by water mcdeltaT we have 50 x c x(100-40)= 200 x 4.2 x (40-30) so C = 2.8
What is the maximum number of 3-inch squares (squares that are three inches on a side) that can be cut from a sheet of tin 19x23 inches? a) 42 b) 48 c) 49 d) 145 e) 146
a) 42 because the needed shape is 3x3, we take 19/3=6, and 23/3=7 then 6x7=42
What is the ratio of the number of composite integers to the number of prime integers in the interval [1,10]? a) 5:4 b) 3:2 c) 1:1 d) 4:5 e) 2:3
a) 5:4 because 2,3,5 and 7 are prime numbers and 4,6,8,9, and 10 are composite. its asking for the ratio of composite to prime numbers.
In the right triangle ABC with right angle at C and AB=14. D is a point on AC with AD=5, and angle BAD= 30 degrees. Which of the following is the length of the line segment BC? a) 7 b) 9 c) 7*sqrt(3) d) sqrt(171) e) sqrt(221)
a) 7 because cos(angleBAD)= BC/AB cos(30)= BC/14 1/2= BC /14 BC=7
The hardest substance known is diamond. Which best describes the structure of diamond? a) A 3D network lattice of covalently bonded carbon atoms b) A 2D network attic of covalently bonded carbon atoms c) A 3D network lattice of carbon ions held together by ionic bonds d) A 3D network lattice of carbon atoms in a sea of mobile valence electrons held together by metallic bonds e) A 3D network lattice of carbon atoms held together by hydrogen bonding and dispersion forces
a) A 3D network lattice of covalently bonded carbon atoms
Ethylene on reaction with bromine forms which among the following product... a) BrH₂C-CH₂Br b) BrH₂C=CH₂Br c) Br₂HC=CHBr₂ d) Br₂HC-CHBr₂ e) none of the above
a) BrH₂C-CH₂Br Because the above reaction between Ethene and bromine is known as electrophilic halogenation reaction and the products usually formed are ethylene dihalides
A study of metabolic rates in a terrestrial community showed that the energy released by respiration exceeded the energy captured in photosynthesis. Which of the following situations is occurring? a) community biomass is decreasing b) community biomass is increasing c) a climax community has been reached d) the second law of thermodynamics is not in effect e) the first law of thermodynamics is not in effect
a) community biomass is decreasing
Primary alcohols undergo what reaction to form alkenes? a) elimination b) oxidation c) reduction d) hydrolysis e) high temperature, high pressure
a) elimination upon elimination or dehydration, the primary alcohols form alkenes.
Which of the following is a characteristic of a fast-moving stream ecosystem? a) high levels of dissolved oxygen b) high salinity c) large numbers of anaerobes d) eutrophication e) thermal stratification
a) high levels of dissolved oxygen because important characteristics of a stream included current, land-water interchange, and oxygen. Water of a shallow, fast-moving stream will have higher oxygen levels than deep, sluggish rivers.
What is the molecular shape and hybridization of the Xe in XeF2? a) linear sp^3d b) trigonal planar sp^2 c) linear sp d) see-saw sp^3d e) pyramidal sp^3
a) linear sp^3d Xe has 8 electrons, F has 7x2= 14 electrons
Which of the following is not undergone by the alkenes? a) mercuration b) oxymercuration c) hydroboration d) halogenation e) none of the above
a) mercuration alkenes do not undergo mercuration, indeed they undergo oxymercuration, a process in which an alkene is covered into an alcohol.
Which statement is incorrect? a) molecular solids such as sugar, sulfur, or ice have high melting points b) SiO2 is an example of a network solid c) Na2S is likely to be a solid at room temperature d) London dispersion < dipole dipole < H-bond < ionic e) all are correct
a) molecular solids such as sugar, sulfur, or ice have high melting points because molecular solids have low melting points and are held together by weaker attractions such as London dispersion forces and dipole-dipole attractions
Barium is an alkaline earth metal with the atomic number 56. Quantum numbers for a valence electron of barium us.... a) n=6, I=0 , m(l)=0 , m(s)=-1/2 b) n=6, I=0 , m(l)=1 , m(s)=-1/2 c) n=6, I=1 , m(l)=0 , m(s)=+1/2 d) n=6, I=2 , m(l)=2 , m(s)=+1/2 e) n=6, I=2 , m(l)=1 , m(s)=+1/2
a) n=6, I=0 , m(l)=0 , m(s)=-1/2 Ba is in the period 6 thus n=6. All alkaline earth metals have 2 valence electrons so we have [Xe]6s^2. Therefore n=6, I=0 m(l)=0 and m(s)=-1/2
During what stage or meiosis do homologous chromosomes exchange genetic information? a) prophase I b) prophase II c) anaphase II d) telophase I e) cytokinesis I
a) prophase I
What will be the reactivity of chlorobenzene in an electrophilic substitution reaction with benzene? a) reacts very slowly compared to benzene b) facts in the same way as benzene c) reacts faster than benzene d) does not react with benzene e) cannot determine
a) reacts very slowly compared to benzene Because the rate of the reaction depends on the electron density in the ring and here in this case resonance is not favorable and the electronegativity dipole dominates. This slows down the reactivity of cholorbenzene.
Which of the following are NOT part of a neuron? a) synapse b) axon c) dendrite d) nissl body e) myelin sheath
a) synapse because neurons communicate with one another at junctions called synapses. at a synapse, one neuron sends a message to a target neuron-another cell. most synapses are chemical; these synapses communicate using chemical messages. Other synapses are electrical; in these synapses, ions flow directly between cells.
Which of the following would result in allopatric speciation? a) two squirrel populations separated by a river b) two birds living in different parts of a tree c) two lion prides living in the same savannah d) a group of insects with the same mating call e) two groups of dogs that have different fur colors
a) two squirrel populations separated by a river allopatric speciation: geographic changes separated two populations of the same species, causing a new species to emerge
Dynemicin A (pictured), a potent anti-tumor antibiotic produced by Micromonosporachernisa, is a potential lead compound in anti-cancer research. How many pi (π) bonds does Dynemicin A possess? a) 10 b) 15 c) 13 d) 12 e) 14
b) 15 Dynemicin A has two aromatic systems, three carbonyl substituents (two ketones, one carboxylic acid), two alkenes and two alkynes. Total = 15. Recall that alkynes possess two pi bonds in addition to one sigma bond
When each of the sides of a square is increased by 1 yard, the area of the new square is 53 square yards more than that of the original square. What is the length of the sides of the original square? a) 25 b) 26 c) 27 d) 52 e) 54
b) 26 New square area - original square area= 53 (a+1)^2 -a^2= 53(a^2 + 2a +1) -a^2= 53 2a+1= 53 2a=52a=26
If x=5 then x+4 is what percent of x^2+2? a) 19 b) 33 1/3 c) 75 d) 300 e) 540
b) 33 1/3 because since x=5, we have x+4=9 and (x^2 +2)=27. Thus, 9/27 *100 = 33 1/3%
In figure A, how many cubes have one of their exposed sides painted? a) 5 cubes b) 4 cubes c) 3 cubes d) 2 cubes e) 1 cube
b) 4 cubes
10 is to 2y as 25x is to a) 5x b) 5xy c) 5x/y d) x/5y e) 5y/x
b) 5xy 10=2y so y=10/2=5. Thus, 25x= 5*5*x=5xy
X is a multiple of A. A is always even, and is always divisible by B. X is also never divisible by C. Which of the following statements must be true? a) A is divisible by C b) X is divisible by B c) Division of X by A equals B d) B is divisible by C e) A time X is always odd
b) X is divisible by B
In the developing embryo, which of the following would be formed from the mesoderm germ layer? a) skin b) blood c) hair d) brain e) lens of the eye
b) blood
Which of the following are responsible for the alignment of the chromosomes along the metaphase plate (equatorial plate) during mitosis? a) molecular chaperones b) centrosomes c) nucleosomes d) nuclear pores e) rRNA
b) centrosomes
which of the following does not come under the organic addition reaction? a) hydration b) dehydration c) halogenation d) hydrohalogenation e) none of the above
b) dehydration dehydration comes under elimination reaction and hence it does not come under addition reaction
Glycosylation, sulfating and phosphorylation (of proteins) represent functions of which cell organelle? a) endoplasmic reticulum b) golgi apparatus c) nucleus d) ribosomes e) centriole
b) golgi apparatus the rough endoplasmic reticulum (RER) has ribosomes on it, which make proteins for the cell to function. the proteins from the EER are sent to the golgi apparatus to be packaged and sent to its final location. the smooth endoplasmic reticulum aids in detoxification, and synthesizes lipids and steroid hormones.
Fire has which of the following effects on a community? a) it causes al of the plants and animals in the community to become dormant b) it recycles dead plant material, thus nutrients become available c) it prevents reestablishment of the prefire community d) it allows for increased mutation rates in these surviving species e) it forces predators to become omnivores
b) it recycles dead plant material, thus nutrients become available Because fire is an ecological shape-shifter. as a reaction, fire is what its circumstances make it. it synthesizes its surroundings.
During photosynthesis... a) light reactions produce sugar, while the calvin cycle produces O2 b) light reactions produce NADPH and ATP, while the calvin cycle produces sugar c) light reactions photophosphorylate ADP, while the calvin cycle produces ATP d) the calvin cycle produces both sugar and O2 e) none of the above
b) light reactions produce NADPH and ATP, while the calvin cycle produces sugar Because light reactions, which convert solar energy into chemical energy (ATP, NADPH) in the thylakoid membranes, fuel the calvin cycle's production of sugars in the stoma
Which among the following is not associated with intermolecular forces? a) they hold neutral molecules b) non-electrostatic in nature c) attraction of oppositely charged particles d) dipole-dipole interaction and van der waals forces e) hydrogen bonding
b) non-electrostatic in nature intermolecular forces are electrostatic in nature
Which of the following is the chemical released by activated cytotoxic T-cells to fight a viral infection? a) actin b) perforin c) tublin d) histamine e) antibodies
b) perforin
Choose the correct increasing frequency trend: a) radio < visible < IR < ultraviolet b) radio < IR < visible < ultraviolet c) IR < radio <visible < ultraviolet d) ultraviolet < IR < radio < visible e) visible < ultraviolet < radio < IR
b) radio < IR < visible < ultraviolet Frequency and energy trend: cosmic rays > gamma rays > X- rays > ultraviolet > visible > IR > microwave > radio waves
Carbonyl compounds especially ketone undergo reduction to form.... a) primary alcohols b) secondary alcohols c) alkanes d) alkenes e) ether
b) secondary alcohols ketones in the presence of NaBH4 undergoes reduction to form secondary alcohols
All of the following are part of the function of the human skeletal system with the exception of: a) the prevention of the lungs collapsing b) sensory transduction c) the fixation of calcium to produce bone d) the production of cells in the immune system e) B & D
b) sensory transduction
Which of the following is an incorrect pairing of a digestive organ with a process? a) esophagus: peristalsis b) small intestine: nutrient absorption c) stomach; acidification d) large intestine; excretion of urea e) all are correct
b) small intestine: nutrient absorption
Which statement is incorrect regarding the boiling points of alkanes? a) boiling point increases with stronger Vander Waal's forces b) surface area is the only factor which determines the boiling point of alkane c) boiling point of straight chain alkanes is greater than that of branched chain alkanes d) the boiling point of cycloalkanes is always higher than that of linear alkanes e) all are correct
b) surface area is the only factor which determines the boiling point of alkane because the number of electrons and surface area are the two factors which determine the boiling point.
Which among the following does not match with the term solubility? a) the structural units get separated from each other b) the ion-dipole bond is very strong c) the spaces in between the structures are occupied by solvent molecules d) the electrostatic attraction between the oppositely charged ions and their corresponding ends are called ion-dipole bond e) more than one correct answer
b) the ion-dipole bond is very strong the bond is weak but in the aggregate they supply enough energy to overcome the inter-ionic forces
Which is correct regarding the synthesis of alkenes? a) cracking of a hydrocarbon yields alkenes b) the reactions are endothermic c) zeolite catalyst helps in the synthesis of alkenes d) the synthesis of alkenes is otherwise known as reforming e) more than one correct answer
b) the reactions are endothermic because the reactions take place at high temperatures and hence they are endothermic.
Which of the following is NOT correct about alkanes? a) alkanes have poor conductivity b) they form hydrogen bonds c) alkanes have less density than that of water d) they have good solubility in non polar solvents than polar solvents e) more than one correct answer
b) they form hydrogen bonds because they undergo polarization and hence they do not form hydrogen bonds
What is the geometry of the central oxygen atom in the ozone molecule? a) linear b) trigonal planar c) tetrahedral d) pyramidal e) T-shape
b) trigonal planar Central oxygen of ozone O3 forms a single bond with one oxygen atom, doubt bond with another oxygen atom and there exits one more non-bonded atom. thus, it forms a trigonal planar structure
Bacteria such as V.cholerae are known to follow an exponential growth curve rate, and will double their number every 15 minutes. Fortunately, anti-bacterial hand wash can kill 99.9% of bacteria on a surface. If a colony of 55 V.cholerae cells are left alone for 2 hours, then anti-bacterial hand wash is applied thoroughly, how many bacterial cells are left? a) 4 cells b) 64 cells c) 128 cells d) 256 cells e) 512 cells
c) 128 cells - 2 hours concert to minutes and divide by 15 min to get the amount of times it doubles (2). You should get 8, 2^8 x 500= 128,000. - After every 15 minutes the amount doubles. there are 8 increments of 15 min within 2hrs. so you just double the amount 8 times. after 15 min you get 1000. after 30 min you get 2000, after 45 min you get 4000. after you do that 8 times you will have 128,000 - after 2 hours you get 128,000. -99.9% of that is 127872. 128,000-127,872= 128
What is the distance on a two dimensional graph between (7,6) and (2,-6)? a) 5 b) 9 c) 13 d) 17 e) sort(153)
c) 13 sqrt((2-7)^2 + (-6-6)^2)= 13
Ben took 9 minutes to walk 3/8 of a mile. At this rate, how many minutes will it take to walk the rest of the mile? a) 11 b) 12 c) 15 d) 18 e) 24
c) 15 because 9 minutes for the first 3/8 mile = a speed of 9min/(3/8miles). Thus, to travel the last 5/8 miles, take 9min/(3/8) * 5/8 mile = 15 minutes
a) 1 cube has two of there exposed sides painted b) 2 cubes have two of their exposed sides painted c) 3 cubes have two of their exposed sides painted d) 4 cubes have two of their exposed sides painted e) 5 cubeshave two of their exposed sides painted
c) 3 cubes have two of their exposed sides painted
If f(x)=3x^2 - 2x, then f(-1) equals a) 1 b) 4 c) 5 d) 7 e) 11
c) 5 f(-1)=3(-1)^2 - 2(-1)=3+2=5
In the normal distribution, what percentage of scores fall within one standard deviation of the mean? a) 33% b) 50% c) 68% d) 75% e) 90%
c) 68%
Which of the following compounds would be most soluble in NH3? a) NaBr b) K2CO3 c) AgBr d) LiNO3 e) CaCl2
c) AgBr Transition metals have a particular tendency to form complex ions, such as Ag(NH2)^2+
Which among the following is formed when an alcohol is dehydrated? a) alkane b) alkyne c) alkene d) aldehyde e) cannot determine
c) alkene In elimination reaction, when protic acids react with alcohol, they lose water molecule to form alkenes.
Which statement is correct? a) Kr has a lower average speed than Ne at the same temperature b) deviations from the ideal gas law are greater at low temperature and high pressure c) all molecules of an ideal gas have the same kinetic energy at constant temperature d) the molecules of a gas undergo many collisions with each other and the container walls e) all are correct
c) all molecules of an ideal gas have the same kinetic energy at constant temperature because at a given temperature, molecules of a gas move at different speeds. There is a common speed that corresponds to the maximum in the Boltzmann distribution curve.
The group of organisms that are amoeboid and exhibit a slug stage are: a) rhizopods b) bryophytes c) cellular slime molds d) dinoflagellates e) zoomastigotes
c) cellular slime molds
This major protein component of connective tissue in mammals comprises most of the organic matter of skin, tendons, bones, and teeth, and occurs in fibrous inclusions in most other body structures a) elastin b) fatty acids c) collagen d) keratin e) phospholipid
c) collagen because collagen is the human body's most abundant protein. It ensures the integrity, elasticity, and strength of our body's connective tissue and thus maintaining the form and function of our skin, cartilage and bones.
The forces responsible for the relativity high melting point and boiling point of water, H₂O, are: a) intermolecular ver der Waals or dispersion forces b) intramolecular covalent bonding c) intermolecular hydrogen bonding d) intermolecular ionic bonding e) intramolecular dipole-dipole forces
c) intermolecular hydrogen bonding
Which of the following is a method for initiating the uptake of a plasmid into a target eukaryotic cell? a) electroporation b) pillus c) lambdaphage viral vector d) heat shock in the presence of CaCl2 e) Both A and D
c) lambdaphage Electroporation and heat shock in the presence of CaCl2 are techniques to make prokaryotes uptake extracellular genome. Pills is used by bacteria for conjugation.
Which of the following is the process by which an unstable nucleus is transformed into a more stable nucleus with lower energy? a) nucleation b) combustion c) nuclear decay d) oxidation e) nucelar fusion
c) nuclear decay
The first step of glycolysis is the phosphorylation of one molecule of glucose to generate glucose-6-phosphate. This reaction: a) is reversible b) occurs in anaerobic organisms only c) prevents glucose from leaking through the plasma membrane d) takes place in the inner membrane of mitochondria e) takes place in the outer membrane of the mitochondria
c) prevents glucose from leaking through the plasma membrane
Which among the following is not an aromatic compound? a) naphthalene b) aniline c) pyridine d) tropolone e) more than one correct answer
c) pyridine pyridine is heterocyclic aromatic compound. whereas naphthalene and aniline are benzenoid aromatic compounds and tropolone is a non-benzenoid aromatic compound
What is the loop of Henle responsible for?
conserving water and minimizing the volume of the filtrate
How many cubic centimeters of water will approximately be required to fill a cylinder with a 3 cm radius and 7 cm height? a) 63 b) 66 c) 132 d) 198 e) 496
d) 198 formula for volume of a cylinder is V=pi*r^2*h
When one of the hydrogen in methane is replaced by a hydroxyl group, then structurally methane resembles? a) water b) ethanol c) methanol d) A and C e) all of the above
d) A and C like water, it is a liquid with boiling point which is abnormally high for a compound of its size and polarity.
Which statement is incorrect? a) Cs is more metallic than Na b) Si, Sb, As, and B are metalloids c) Hg is better electrical conductor than S d) C-C bond is stronger than an Si-O bond e) O2 is the most abundant element found in the human body
d) C-C bond is stronger than an Si-O bond because Silicon is a metalloid that forms a very strong Si-O bond, such as SiO2
4-chlorobut-1-ene is the name of which among the following alkenes a) CH₂Cl-CH₂=CH-CH₂ b) CH₂Cl-CH₂-CH-CH₂ c) CH₂CL=CH₂=CH=CH₂ d) CH₂Cl-CH₂-CH=CH₂ e) Cl-CH=CH-CH₂-CH3
d) CH₂Cl-CH₂-CH=CH₂ Because the structure CH₂Cl-CH₂-CH=CH₂ has the name 4Chlorobut-1-ene according to the IUPAC naming system .
DNA polymerase catalyze the production of polynucleotide chains. which of the following statements holds true: a) DNA polymerase do not require a primer in order to initiate the reaction b) DNA polymerase require a primer with a free 5'-end c) DNA polymerase require a primer base-paired to the template with a free 5'-end d) DNA polymerases require a RNA primer base-paired to the template and with a free 3'-end e) DNA polymerases require a DNA primer base-paired to the template and with a free 5'-end
d) DNA polymerases require a RNA primer base-paired to the template and with a free 3'-end
Which is the best leaving group in a substitution reaction on alkyl halide from the following choices? a) F- b) Cl- c) Br- d) I- e) all are equally good leaving groups
d) I- weaker bases are better leaving groups. Iodine is the least electronegative. it is also the most stable molecule,making it a better leaving group
Which of the following molecules has a bond that is nearest to a pure covalent bond? a) NaCl b) MgSO4 c) SiO2 d) N2 e) AgO
d) N2
Which of the following is the correct pairing of the extraembryonic membrane and its function? a) yolk sac - fluid sac that protects the growing embryo. b) amnion - provides food for the growing embryo. c) chorion - stores waste for the embryo. d) allantois - participates in gas exchange. e) placenta - provides cushion for the embryo
d) allantois - participates in gas exchange. The yolk sac provides food for the growing embryo, especially true with birds. The amnion forms the fluid filled sac that provides for cushion and protection to the embryo. The chorion is the outermost membrane, encasing the other extraembryonic membranes. Only answer option D is correctly paired.
A sample of bacteria was discovered in a hot spring and contained a cell wall of various polysaccharides. Which of the following would be the correct categorization of the bacteria? a) protostome b) eubacteria c) eukaryotic d) archaebacteria e) deuterstome
d) archaebacteria
Which of the following would be best to use for population growth with known upper limit? a) cos(x) b) √x c) -|x| d) ex e) x!
d) ex
Which is not a step in pinocytosis? a) an inducer molecules binds to a receptor on the cell membrane b) an invagination forms, surrounding part of the extracellular fluid c) the particles are brought into the cell via a vesicle d) lysosomes digest the contents of the vesicle e) none of the above
d) lysosomes digest the contents of the vesicle D is not involved in pinocytosis, but it is involved in phagocytosis
The major fibrous proteins are... a) peptone and edestin b) gluten and leucine c) valine and lysine d) myosin and actin e) more than one correct answer
d) myosin and actin because myosin is a motor protein that generates the force in a muscle contraction. actin is a spherical protein that forms, among other things, the thin filament in muscle cells. In skeletal muscle, each myosin thick filaments is surrounded by the actin thin filaments and each thin filament is surrounded by thick filaments.
The fundamental mechanism of evolution whereby an organism changes on its own as a result of environmental influence is called ...? a) differential reproduction b) mutation c) migration d) natural selection e) genetic drift
d) natural selection
A crystalline solid possess which of the following property? a) irregularity b) non-stability c) non-symmetric d) perfect geometric pattern e) more than one correct answer
d) perfect geometric pattern a crystalline solid is one which possesses perfect geometry, high stability, symmetric and regularly arranged
Melatonin is produced by which of the following? a) skin b) liver c) pituitary gland d) pineal gland e) A and D
d) pineal gland because the pineal gland synthesizes and secretes melatonin, a structurally simple hormone that communicates information about environmental lighting to various parts of the body.
alkene under high temperature and high-pressure forms... a) alcohol b) polyalkyne c) aldehyde d) polyalkane e) polyalkene
d) polyalkane because alkenes undergoes polymerization reaction under high temperature and pressure to form poly alkanes -(C-C)-n.
Which among the following is not a property of Ionic bond? a) losing of electrons b) gain of electrons c) sharing of electrons d) transfer of electrons e) more than one correct answer
d) transfer of electrons
Which is the correct statement regarding carboxylic acids? a) they form acyl chlorides on reaction with PCl5 b) aldehydes in the presences of H^+/Cr2O7 forms carboxylic acids c) they combine with alcohols to form esters d) upon polymerization, they form polymers e) none of the above
d) upon polymerization, they form polymers because carboxylic acids do not undergo polymerization reaction
What are pi bonds?
double or triple bonds
Which of the following values contain 5 significant figures? a) 0.0005 b) 0.0500 c) 0.0005 d) 0.0050 e) 0.50000
e) 0.50000 because zeros are not significant after decimal and before non-zero numbers. all non-zero numbers are significant. zeros after non-zero numbers in a decimal are significant.
If 1 inch equals 2.5 centimeters, then 25 meters equals how many inches? a) 0.01 b) 0.1 c) 10 d) 62.5 e) 1,000
e) 1,000 25m=2,500 cm 2,500 cm x 1 in / (2.5 cm)= 1,000 inches
a) 1 cube has two of their exposed sides painted b) 2 cubes have two of their exposed sides painted c) 3 cubes have two of their exposed sides painted d) 4 cubes have two of their exposed sides painted e) 5 cubes have two of their exposed sides painted
e) 5 cubes have two of their exposed sides painted
How many unpaired electrons are in Molybdenum? a) 0 b) 2 c) 3 d) 5 e) 6
e) 6 because [Kr] 4d^5 5s^1
Which statement is correct? a) elastic collisions occur, gases are in constant random motion b) gases move at various speeds and in every possible direction c) the average kinetic energy of gas is proportional to the absolute temperature d) gasses are separate by greater distances than their own dimensions; volume occupied is negligible e) all are correct
e) all are correct all of these statements are true regarding the kinetic theory of gases
Of the following, which mechanism(s) is important in the death of erythrocytes in human blood? a) phagocytosis b) hemolysis c) mechanical damage d) pinocytosis e) all except D
e) all except D Phagocytes are a type of white blood cell that use phagocytosis to engulf bacteria, foreign particles, and dying cells to protect the body. Pinocytosis and phagocytosis are similar processes, but they have some key differences. Phagocytosis is used to absorb materials much bigger than the particles that can be absorbed by pinocytosis, such as bacteria. Phagocytosis involves the ingestion of liquids and solute particles. Hemolysis breakdown or destruction of red blood cells so that the contained oxygen-carrying pigment hemoglobin is freed into he surrounding medium.
What is correct about electrolysis of water? a) oxygen gas is produced at the anode b) hydrogen gas is produced at the cathode c) in the net reaction, hydrogen moles are 2x the oxygen moles d) passing electricity through liquid water produces hydrogen and oxygen gas e) all of the above
e) all of the above because consider the net reaction of electrolysis of water 2H2O(I) --> 2H2(g) + O2(g)
Alcohol on refluxing with Cr2O7 gives...? a) ester b) aldehyde c) sugar d) ether e) carboxylic acid
e) carboxylic acid because when alcohol (R-OH) is refluxed with Cr2O7, it forms carboxylic acid (R-COOH).
For all x, the cos(x) is equal to a) sin(x) b) cos (x +pi) c) sin(-x) d) sin(x) + cos(x) e) cos(-x)
e) cos(-x) cos(x)=cos(-x) for all x
The enthalpy of a system of gas is dependent on which of the following? a) pressure only b) volume only c) internal energy only d) pressure and volume e) pressure, volume and internal energy
e) pressure, volume and internal energy
How does the C-N bond in CN-1 differ from the C-H bond in CH4? a) the C-H bond is longer because it is a double bond. b) the C-N bond is longer because it is a single bond. c) the C-H bond is shorter because it is a double bond. d) the C-H bond is shorter because it is a triple bond. e) the C-N bond is shorter because it is a triple bond.
e) the C-N bond is shorter because it is a triple bond.
Which of these properties is not a colligative property of a salt solution? a) lowering of vapor pressure with increasing concentration b) elevation of the boiling point with increasing concentration c) depression of freezing point with increasing concentration d) osmotic pressure increases with increasing concentration e) the lower density of ice than the solution from which it forms
e) the lower density of ice than the solution from which it forms
Which piece of laboratory glassware is best used to measure 1.00 L of solution accurately? a) beaker b) buret c) volumetric pipette d) measuring cylinder e) volumetric flask
e) volumetric flask
What does amphipathic mean?
having both a hydrophilic region and a hydrophobic region
What is apoptosis?
process of programmed cell death
