Missed questions UW
D. Beta decay typically involves the emission of a nuclear electron or positron, but sometimes an electron capture can occur. Electron emission increases the atomic number by one whereas positron emission and electron capture both decrease the atomic number by one. (electron capture : is a special form of beta decay in which a nucleus absorbs an electron from an external source without emitting a particle. The absorbed electron converts a proton into a neutron, decreasing the atomic number by one.)
90^Sr is converted to 90^Y by which of the following processes? A. Electron capture B. Positron emission C. Gamma ray emission D. Beta minus decay
A. The ability of a protein to maintain its three-dimensional folded form (tertiary structure) is known as conformational stability. Conformational stability can be measured by melting temperature Tm, the temperature at which half of the proteins in solution are folded and half are denatured. A lower Tm indicates decreased conformational stability because less thermal energy is required to denature the protein. The ability of a folded enzyme to catalyze a reaction is measured by the turnover number kcat, which represents the number of reactions catalyzed per second per active site in solution. A change in the conformational stability of an enzyme does not necessarily affect function, as long as the ambient temperature is low enough that the protein can fold properly.
A certain enzyme uses Mn2+ as a cofactor under physiological conditions, and scientists hypothesize that Mn2+ is required for stabilization of tertiary structure but not for enzyme activity. Which of the following observations is consistent with this hypothesis? A. Substitution of Mg2+ in place of Mn2+ yields a decreased melting temperature and no change in the kcat of folded proteins. B. Replacing Mn2+ with Cu2+ yields an unchanged melting temperature and a decreased kcat of folded proteins. C. Using Ni2+ in place of Mn2+ yields a decreased melting temperature and a kcat value of zero. D. Removing Mn2+ yields an increased melting temperature and no change in the kcat of folded proteins.
A. Increasing the temperature increases the average kinetic energy of the membrane components, and therefore increases fluidity. Conversely, decreasing the temperature decreases membrane fluidity This kink prevents tight packing and reduces the strength of the intermolecular forces, and therefore increases membrane fluidity. The question asks which sample has the highest iodine value. The iodine value reports the amount of pi bonds and correlates with the sample that has the highest amount of unsaturated fatty acids. Because unsaturated fatty acids increase fluidity, they would be upregulated as a homeostatic response to decreased fluidity at lower temperatures. Therefore, the sample from cells grown at 30 °C will most likely have the highest iodine value.
A scientist cultured samples of a cell line at three different temperatures: 30 °C, 37 °C, and 39 °C. She then extracted and isolated the membrane phospholipids of each sample and measured the iodine value, which quantifies the number of pi bonds that react with halogens such as iodine. Which sample most likely has the highest iodine value? A. The sample from cells grown at 30 °C B. The sample from cells grown at 37 °C C. The sample from cells grown at 39 °C D. All samples should have the same iodine value.
C. According to the passage, the basilar membrane is modeled as a resonator system. The resonant frequency of an object is the frequency that causes relatively large oscillations compared to other frequencies. The resonant frequency depends on the physical characteristics and geometry of the object. As shown in Figure 1, high frequencies resonate near the base of the basilar membrane, and low frequencies resonate near the apex. The frequency of a sound is associated with its perceived pitch (or tone). A sound with a high frequency is perceived to have a high pitch, and a sound with a low frequency (such as those near the apex) is perceived to have a low pitch. The frequency of a sound is associated with its perceived pitch; high-frequency sounds have high pitches. The low-frequency sounds that cause resonance near the apex of the basilar membrane are characterized by low pitches.
A sound wave used in PTA that causes resonance close to the apex of the basilar membrane has a relatively: A. short wavelength. B. high intensity. C. low pitch. D. large phase shift.
D. torque= r F sin theta = 2.5 × 10^11 N∙m in the counterclockwise direction torque is in the direction of applied force, so since the force is being applied ccw, then it should be ccw. torque is just the force created that makes something spin. so if you think of like a fidget spinner, if you push one side of it in a ccw direction, it'll spin ccw, this meaning torque was applied ccw
A star orbiting a black hole in the clockwise direction begins to slowly spiral inward due to a counterclockwise drag force. When the star's radial distance from the black hole is 1.0 × 10^6 km, a drag force of 250 N acts perpendicular to the orbit radius. What is the torque on the star? A. 0 N∙m B. 2.5 × 10^9 N∙m in the counterclockwise direction C. 2.5 × 10^11 N∙m in the clockwise direction D. 2.5 × 10^11 N∙m in the counterclockwise direction
B. 2 revs = 720 degrees Our angular velocity is (720degrees/20hours) Now lets unit convert: (720degrees/20hours)*(1hour/3600seconds)=0.01 revolutions/second
A star orbiting a supermassive black hole makes two approximately circular revolutions around the black hole every 20 hours. What is the approximate angular velocity of the star? A. 5.0 × 10-3 degrees/second B. 1.0 × 10-2 degrees/second C. 3.0 × 10-1 degrees/second D. 6.0 × 10-1 degrees/second
C. Single-stranded genomes, however, can be found in certain viruses but not in eukaryotic cells. Eukaryotic cells instead contain double-stranded DNA genomes. Eukaryotic cells can be distinguished by their unique characteristics. They have a genome with multiple linear chromosomes (double-stranded DNA). They also use meiosis as one mechanism of cell division (sexual reproduction), and they have membrane-bound organelles.
A student analyzing dividing cells of a certain type under the microscope finds that each daughter cell produced contains half the number of chromosomes as its parent cell. Given this, cells of this type would most likely contain all of the following EXCEPT: A. peroxisomes. B. nuclear pore proteins. C. single-stranded genomes. D. microtubules.
B. Synthetic cortisol analogues have a molecular structure that resembles that of endogenous cortisol, and therefore are able to mimic the effect of cortisol by binding hypothalamic and pituitary cortisol receptors. Although the analogueconcentration is determined by the amount administered, interaction of the analogue with cortisol receptors will induce negative feedback that reduces the synthesis and secretion of endogenous cortisol by the adrenal glands. Therefore, after treatment with a synthetic cortisol analogue, the patient's serum level of endogenous cortisol would decrease due to negative feedback.
A woman with low serum cortisol due to partial adrenal dysfunction is treated with high doses of a synthetic cortisol analogue. According to Figure 2, treatment with a cortisol analogue will most likely cause this patient's serum level of endogenous cortisol to: A. increase only. B. decrease only. C. remain the same. D. increase at first, but then decrease over time.
A. Acids catalyze many reactions by donating protons to a reactant. Protonation enhances electrophiles and increases the stability of leaving groups. Acids generally decrease the nucleophilicity of molecules.
Acid helps catalyze the Fischer esterification reaction by doing all of the following EXCEPT: A. enhancing the nucleophilicity of alcohols. B. forming a resonance-stabilized intermediate. C. creating a good leaving group. D. increasing carbonyl electrophilicity.
B. The question describes the exchange of two ions (Na+ and Ca2+) across the plasma membrane of cardiac cells by a membrane protein (ie, the protein is an antiporter). This Na+/Ca2+exchange occurs after depolarization, which causes an increase in the intracellular Ca2+ concentration. Because depolarization is a reduction in membrane potential (ie, voltage), this information suggests that depolarization promotes entry of Ca2+ ions through a voltage-gated membrane channel (ie, a channel that opens in response to a change in membrane potential). can't be D bc The question indicates that Ca2+ transport from intracellular to extracellular space requires energy input; therefore, Na+/Ca2+ exchange involves transport against the calcium gradient. However, the voltage-gated channel facilitates Ca2+entry into the cell, which must occur down the gradient.
After cardiac cells depolarize under physiologically normal conditions, extracellular Na+ enters the cells via a specific plasma membrane protein. The Na+ transport provides the energy needed to pump intracellular Ca2+ to the extracellular space. This Na+/Ca2+ exchange depends on a preceding increase in intracellular [Ca2+] in response to the cell's decreased electric potential. This preceding increase in Ca2+ is most likely evidence of: A. direct voltage-dependent activation of the exchanger. B. entry of Ca2+ ions into the intracellular fluid through a voltage-dependent membrane channel. C. activation of a ligand-gated Ca2+ channel. D. transport of Ca2+ ions against their concentration gradient through a voltage-gated membrane channel.
B. In cDNA cloning, reverse transcriptase generates a single strand of cDNA from a target mRNA sequence. DNA polymerase synthesizes the second complementary DNA strand and amplifies the target cDNA sequence. The target cDNA can then be inserted into a plasmid vector via the actions of a restriction enzyme (cuts both plasmid and vector) and DNA ligase (joins the cDNA to the vector). RNA polymerases synthesize various types of RNAs but are not used as standard reagents in cDNA cloning because the target mRNA is already present in the cell (ie, does not need to be synthesized).
All of the following enzymes would be directly used to generate the vector transfected into BLM+ cells EXCEPT: A. Reverse transcriptase B. RNA polymerase C. DNA polymerase D. Restriction enzyme
C. An object thrown upwards: begins as KE (leaving thing that is throwing object upwards) and at the top of the hill (/path) all energy equals PE. The kinetic energy of an object launched upward in gravity is converted into gravitational potential energy.
An object is launched with a one-time burst of propulsion away from the surface of the Moon. After the burst, which of the following best describes the changes that occur as the object moves away from the Moon's surface? A. The object mass is dissipated as heat. B. Potential energy is converted into kinetic energy. C. Kinetic energy is converted into potential energy. D. Total mechanical energy is not conserved.
futile cycle
Anabolic and catabolic pathways must be carefully balanced according to the energetic and material needs of the cell. When anabolic and catabolic lipid metabolism occur at the same rate simultaneously, fatty acids are built up only to be immediately broken down, leading to wasted energy with no material gain. this is called ________
B.
Antacids act by functioning chemically as weak Brønsted-Lowry bases that neutralize excess stomach acid. Equations 1 and 2 describe the chemical behavior of the antacid sodium bicarbonate with stomach acid (HCl). NaHCO3(aq) + HCl(aq) → H2CO3(aq) + NaCl(aq) Equation 1 H2CO3(aq) → CO2(g) + H2O(l) Equation 2 In Equation 1, carbonic acid (H2CO3) and sodium chloride form during a: A. single replacement reaction. B. double replacement reaction C. combination reaction. D. decomposition reaction.
B. pH= 6.2 Ka= 4 x10^-5 Ka= [H+][A-]/[HA] u could find/solve pKa from pKa= - log (Ka). or u could recognize that pKa= 5 from Ka equation. pH > pKa. = deprotonation. deprotonation occurs as pH increases (solution is becoming more basic) Thus, less moles of the weak acid and more moles of the CB. If the pH of a solution is less than the pKa (ie, the solution is more acidic), the equilibrium is shifted toward a greater concentration of the protonated acid (ie, [HA] > [A−]). Conversely, if the pH is greater than the pKa (ie, the solution is more basic), the equilibrium is shifted toward a greater concentration of the deprotonated conjugate base (ie, [HA] < [A−]).
Assume HNO2 dissociates in water with a Ka of 4 × 10−^5 at 298 K. HNO2(aq) ⇄ NO2−(aq) + H3O+(aq) An aqueous solution containing a mixture of HNO2 and NO2− has a pH of 6.2 at 298 K. Compared to the concentration of NO2−, the concentration of HNO2 must be: A. greater, because the pH of the solution is greater than its pKa. B. less, because the pH of the solution is greater than its pKa. C. greater, because the pH of the solution is less than its pKa. D. less, because the pH of the solution is less than its pKa.
C. When relative motion exists between a sound source and an observer, the observed frequency and wavelength differ from that of the original frequency and wavelength. This phenomenon is known as the Doppler effect. When the source moves toward the observer, the observed wavelength decreases and the observed frequency increases.
Audiometry can also be used to evaluate a subject's ability to localize a moving sound source. When the sound source is moving toward the subject, which of the following increases? A. The observed wave velocity B. The observed period C. The observed frequency D. The observed wavelength
A scientist purified the transducin protein and all downstream components for further study in vitro. Addition of which of the following will be necessary to activate the purified transducin? A. Electric stimulation B. High levels of GTP C. Irradiation by light energy D. Addition of nonspecific protein kinases
B. G protein-coupled receptors (GPCRs) are 7-transmembrane integral membrane proteins that serve a critical role in many cell signaling pathways. In the resting state, the intracellular portion of a GPCR binds to a heterotrimeric G protein, and the G protein binds to a GDP molecule. During a cell signaling event, a typical GPCR binds an extracellular ligand that acts as an agonist to activate the GPCR. The activated GPCR then activates the coupled heterotrimeric G protein by catalyzing the exchange of GDP for GTP. The activated G protein can then activate additional downstream processes. The passage states that the opsin proteins are GPCRs activated by the light-stimulated cis-trans isomerization of retinal rather than by the binding of an extracellular ligand. The passage further states that the transducin is the heterotrimeric G protein associated with opsins. The question states that only transducin and its downstream components have been purified; opsins, which act upstream of transducin, have not been purified. To activate transducin, GTP must be exchanged for GDP. In the absence of coupled opsin proteins, this can be accomplished by high levels of GTP, which can compete for the GDP/GTP binding site of transducin to activate it.
C. 0.05 L x 0.005 mol/1 L x 40g/1 mol = 0.01g
Based on the information in the passage, what is the mass of calcium (MW = 40.1 g/mol) in the Sample 1 mixture? A. 0.003 g B. 0.005 g C. 0.01 g D. 10 g
C. (the interior compartment, lumen) of the SER contains enzymes that synthesize lipids, including cholesterol and cholesterol-derived molecules (eg, steroid hormones). CTH is released by the anterior pituitary and acts on the adrenal cortex to promote the synthesis and secretion of cortisol, a steroid hormone produced from cholesterol. However, the actual synthesis of this steroid hormone depends on the availability of cholesterol from transport into the cell and from production of cholesterol by SER proteins, not ACTH. Consequently, defective SER proteins can compromise cortisol synthesis within the adrenal cortex regardless of ACTH stimulation. Accordingly, patients with adrenal insufficiency caused by defective SER proteins can exhibit a limited response to ACTH administration. Synthesis of lipids and steroid hormones takes place within the smooth endoplasmic reticulum.
For individuals who exhibit insufficient hormone production by the adrenal cortex, ACTH is sometimes administered as a treatment option. Clinicians have reported that most patients fail to respond to this treatment with ACTH. A possible reason for this outcome is that nonresponsive patients: A. release insufficient amounts of ACTH from the pituitary gland. B. continuously overexpress the genes for DBH and PNMT. C. exhibit impaired cholesterol synthesis in the smooth endoplasmic reticulum of adrenocortical cells. D. express an overactive ACTH receptor on cells responsive to cortisol.
C. The electrolysis of water is driven by an external power source, indicating a nonspontaneous reaction with ΔG° > 0 and E°cell< 0. In an electrolytic cell, a redox reaction converts electrical energy (from an external source) into stored chemical energy. The Gibbs free energy ΔG° produced from this conversion represents the maximum amount of electrical work that can be performed during the reaction. The associated electromotive force (emf) is the amount of energy applied by the external power source per unit of electric charge. The Gibbs free energy ΔG° for a redox reaction is related to the number of electrons transferred per reaction (n), the standard cell potential (E°cell), and Faraday's constant (F), according to the equation ΔG° = −nFE°cell. For a spontaneous reaction, ΔG° < 0 and E°cell > 0; for a nonspontaneous reaction, ΔG° > 0 and E°cell< 0.
Gel electrophoresis is a widely used technique that separates charged macromolecules, such as negatively charged DNA and RNA, according to their molecular size. An electrophoretic system operates as an electrolytic cell in which a direct electric current is applied to two metal electrodes immersed in a conducting electrolyte solution. The force from the resulting electric field causes the charged macromolecules to migrate through a porous agarose gel at a rate that is inversely related to their size. The electrolysis of water is a: A. spontaneous process with ΔG° > 0 and E°cell < 0. B. spontaneous process with ΔG° < 0 and E°cell > 0. C. nonspontaneous process with ΔG° > 0 and E°cell < 0. D. nonspontaneous process with ΔG° < 0 and E°cell > 0.
mitochondrial Matrix
High pH= low proton concentration
A. Norepinephrine and epinephrine are released by the adrenal medulla and modulate the metabolism of glycogen, the storage form of glucose. Both hormones promote the breakdown of glycogen into glucose monomers in a process known as glycogenolysis. By inhibiting the enzymes that mediate glycogen synthesis, norepinephrine and epinephrine also inhibit glycogenesis (ie, the formation of glycogen from glucose).
Hormones secreted by the adrenal medulla most likely influence energy metabolism by: A. inhibiting proteins that mediate glycogen synthesis. B. activating their cytosolic receptors in target cells. C. reducing the activity of enzymes that catalyze fat hydrolysis. D. increasing the activity of proteins that inhibit gluconeogenesis.
C. 5.0 x 10^-3 mol/L x 500 x 10^-3 L x 66g/1 mol = 1.6 x 10^-1
How many grams of lithium acetate were mixed in 500. mL of water to prepare the 5.0 × 10^−3 M lithium acetate solution? (Note: The molar mass of lithium acetate is 66 g/mol.) A. 3.8 × 10^−5 g B. 2.5 × 10^−3 g C. 1.6 × 10^−1 g D. 1.6 × 10^2 g
D. 110-70=40 dB= 10 log I/I2 10^4= I/I2 Sound intensity is typically measured in units of decibels (dB). The dB scale is logarithmic, so increasing the intensity of a sound by 10 dB corresponds to a factor of 10 increase in intensity.
How many times greater is the intensity of the sound from a 1.0 T MRI scanner compared to the intensity of the sound from a vacuum cleaner? A. 40 B. 100 C. 1,000 D. 10,000
A. The Lorentz forceF acts on a chargeq moving in a magnetic fieldB with velocity v. The direction of F is perpendicular to both the direction of v and the direction of B. The magnitude of F equals the product of q, v, B, and the sine of the angle θB between the directions of v and B: F= q vB sin θ The workW done by F on an object equals the product of F, the magnitude of the object's displacement d, and the cosine of the angle θ between the directions of d and F: W=Fd cos θ In this question, the value of B increases, which causes F to increase. However, the value of θ is always 90° because d is the same direction as v, and F is always perpendicular to v. Therefore, W must always equal 0 J because cos 90° is always equal to 0.
How will the work done by the Lorentz force on an electron traveling through the magnetic field of an MRI scanner change if the magnetic field strength is increased? A. The work will not change, because it is always zero. B. The work will increase, because the velocity of the electron will increase. C. The work will increase, because the force on the electron will increase. D. The work will decrease, because the velocity of the electron will decrease.
combustion
Hydrocarbon (alcohol, or organic compound) + O2 --> CO2 + H2O
C. The question states that the frameshift mutation increased the length of the protein from 591 to 626 amino acids. The approximate molecular weight of a protein can be determined by multiplying the number of amino acids by the average weight of a single amino acid (110 Da), so a protein with 591 amino acids (wild type) would have a molecular weight of approximately 65,000 Da, or 65 kDa (110 Da/amino acid × 591 amino acids ≈ 65,000 Da). The molecular weight of the mutant protein is 110 Da/amino acid × 626 amino acids ≈ 69,000 Da, or 69 kDa. The difference in molecular weight between 69 kDa and 65 kDa is 4 kDa. Alternatively, the answer may be determined by the difference in the number of amino acids (626 − 591 = 35 amino acids) multiplied by 110 (35 amino acids × 110 Da/amino acid = 3850 Da ≈ 4 kDa).
If a frameshift mutation changes the number of amino acids in a protein from 591 to 626, the difference between molecular weights of the wild-type and mutant proteins would be closest to: A. 1 kDa B. 2 kDa C. 4 kDa D. 8 kDa
mitochondrial Mitochondria have their own genetic material, which is passed down through the maternal line. Mitochondria have circular DNA inside them (Note the endosymbiosis theory states that mitochondria are of bacterial origin). So if the mother is affected by a mitochondrial disorder, the child will also be affected. Mitochondria are cellular organelles that have their own genome; their main functions include ATP generation, heat production, and beta-oxidation of fatty acids. Mitochondria within sperm are not transferred into the ovum during fertilization; therefore, males never pass on their mitochondria.
If all children of affected mothers have the condition, but no children of affected fathers and healthy mothers do
C. The intensity of sound is measured on a logarithmic scale with units of decibels (dB). For each decrease in 10 dB, the sound intensity decreases by a factor of 10. Therefore, a decrease in 30 dB is equal to a 1,000-fold decrease in intensity. intensity = power/area α energy/area higher intensity= more energy/area
In Figure 2, how does the hearing threshold intensity at 1,500 Hz compare to the threshold intensity at 2,000 Hz? A. It is 30 times less intense. B. It is 30 times more intense. C. It is 1,000 times less intense. D. It is 1,000 times more intense.
D. Long bone grows in length by a process where chondrocytes (cartilage-producing cells) divide and produce collagen to which calcium phosphate attaches to form hardened bone. The chondrocytes are located at the interface between the long shaft (diaphysis) and the widened ends (epiphyses) of long bones, and this cartilaginous region is known as the epiphyseal (growth) plate. The cell division and collagen added to this region force the epiphyses and diaphysis farther apart, thereby increasing the length of the bone. The activity of the chondrocytes producing the cartilage of the growth plate stops when linear growth of long bones is complete (except during fracture healing). Long bone growth occurs when chondrocytes in the growth plate divide and produce collagen, to which calcium phosphate crystals attach to form hardened bone. When chondrocytes in bone stop dividing, bone growth is complete.
In adults, which of the following cell types would be LEAST active in healthy long bones? A. Osteoblasts B. Osteoclasts C. Bone marrow cells D. Chondrocytes
B. Atoms are most stable when they have a full outer orbital shell (valence shell). For this reason, the chemical behavior of an atom is determined largely by the number of valence electrons because this number determines how many electrons must be gained or lost to achieve stability. Accordingly, elements in the same column of the periodic table have the same valence electron configuration, and therefore have similar chemical properties (ie, react with other elements in similar ways). In contrast, physical properties of elements in the same column are still often dissimilar because physical properties (eg, color, density, atomic radius) are determined by atomic characteristics other than the valence electrons.
In its nuclear decay chain, 90^Sr decays into 90^Y, and 90^Y then decays to 90^Zr. Which of the following elements exhibits chemical properties most similar to zirconium-90? A. 90^Nb B. 174^Hf C. 46^Sc D. 48^Ca
D. The Lorentz force exerted on a moving charge in the presence of a magnetic field is perpendicular to the particle's velocity. As a result, the charge's trajectory is forced into a curved path, with negative charges and positive charges bent in opposite directions. Because an electron is less massive than a proton, an electron's path would be more curved in the same magnetic field.
In the presence of an external magnetic field (not shown), a proton initially traveling upward is deflected into the path labeled as A in the following figure. An electron with the same initial velocity as the proton travels through the magnetic field. What would be the expected path of the electron? A. A B. B C. C D. D
C. 0.1 mol LaCl3/1L (3 moles Cl-/1 mol LaCl3)= 0.3 M
Lanthanum(III) chloride (MM = 245.25) can be used to eliminate chemical interference in a sample by competitively binding to PO43−, releasing calcium to be atomized in the flame for detection. The students prepared unknown Samples 1 and 2 by mixing 25 mL of reservoir water, 16 mL of 2% HNO3, and 9 mL of 0.1 M LaCl3 for a total sample volume of 50 mL each. The samples were each tested three times using flame AA spectroscopy, yielding the results reported in Table 1. what is the molar concentration of Cl− ions in a solution prepared by dissolving 0.1 moles of lanthanum(III) chloride in 1 L of water? A. 0.03 M B. 0.1 M C. 0.3 M D. 30 M
Catabolic hormones
Liver: Sugar release Adipose tissue: Lipid release & oxidation Muscle: Muscle energy use. Glucagon, Epinephrine, Cortisol
Anabolic hormones.
Liver: Sugar storage Adipose tissue: Lipid storage Muscle: Muscle growth Insulin, GH (growth hormone), Testosterone, Estrogen
C. The question asks about an experimental result that would provide evidence that a drug causes cells to carry out increased beta oxidation (ie, increased breakdown of fatty acids into acetyl-CoA in the mitochondria). Because malonyl-CoA inhibits long-chain fatty acid transport into the mitochondria, beta oxidation is decreased in the presence of malonyl-CoA. If treatment with a drug led to lower levels of cytosolic malonyl-CoA, beta oxidation could increase as more fatty acids enter the mitochondria. Therefore, the observation that treatment with a drug results in a decreased concentration of cytosolic malonyl-CoA would be one piece of evidence to suggest that the drug causes increased beta oxidation Malonyl-CoA helps regulate fatty acid metabolism by inhibiting long-chain fatty acid transport into the mitochondria. (decrease Malonyl-CoA= increase in FA transport to the mito& as a result increase beta oxidation).
Malonyl-CoA is an intermediate in fatty acid synthesis and an inhibitor of long-chain fatty acid transport to the mitochondria. Given this information, which of the following experimental results would provide evidence that a certain drug causes cells to carry out increased beta oxidation? A. Adding malonyl-CoA to drug-treated cells causes an increase in the level of cytosolic acetyl-CoA compared to cells without malonyl-CoA treatment. B. Adding malonyl-CoA to drug-treated cells causes a decrease in the level of mitochondrial acetyl-CoA compared to cells without malonyl-CoA treatment. C. Treating cells with the drug results in a decreased concentration of cytosolic malonyl-CoA compared to untreated cells. D. Treating cells with the drug results in an increased concentration of cytosolic malonyl-CoA compared to untreated cells.
A. Objects with high energy have a higher temperature and emit EM waves with relatively higher frequencies and energy. Radiation energy is directly related to the temperature of the object that emits the radiation. Hotter objects radiate waves in the higher frequency region of the spectrum; conversely, colder objects radiate waves in the lower frequency region. For example, the human body radiates infrared light (ie, with frequencies just below those of visible red light). higher frequency, higher energy, higher temperature.
Matter falling in the gravitational field of a central mass can form a hot, charged fluid. The fluid matter orbiting some stars radiates infrared light, but the matter orbiting black holes emits x-rays. Which of the following explains this discrepancy? The matter orbiting black holes must: A. be hotter than the matter orbiting stars. B. be colder than the matter orbiting stars. C. have lower kinetic energy than the matter orbiting stars. D. exhibit higher viscosity than the matter orbiting stars.
groups/columns vertical
Members of the same group in the table have the same number of electrons in the outermost shells of their atoms and form bonds of the same type. have the same valence electron configuration, and therefore have similar chemical properties (ie, react with other elements in similar ways). Chemical behavior is governed largely by the number of electrons in an atom's valence shell. Atoms with the same number of valence electrons (ie, in same ______ of the periodic table) have similar chemical properties.
aliphatic
Non-aromatic. Side chain contains only C and H. GLAMVIP
A. An SN2 reaction is a single-step reaction in which a nucleophile reacts with an electrophile, and a leaving group is simultaneously released from the electrophile. If the electrophile in an SN2 reaction is a chiral center, its stereochemistry will always be inverted by the reaction: an electrophile in the S configuration prior to the reaction will adopt an Rconfiguration after the reaction, and vice versa if the nucleophile has the same priority ranking as the leaving group. SN2 reactions result in the inversion of configuration of the electrophile if the electrophile is a chiral center. An electrophile in the S configuration will adopt the R configuration after the reaction and vice versa.
Prior to the reaction, what was the configuration of the carbon bonded to deuterium? A. S, because the configuration is inverted by the reaction B. R, because the configuration is inverted by the reaction. C. S, because the configuration is preserved by the reaction D. R, because the configuration is preserved by the reaction
I > Br > Cl I is the largest
SN2 reactions occur when a nucleophile donates electrons to an electrophile with a good leaving group. A leaving group is removed from a molecule when the electrons in the bond are transferred to an atom in the leaving group. Therefore, a good leaving group must be able to stably carry the negative charge conferred by these electrons. Good leaving groups must be able to stably carry the electrons they receive. Halogens are generally good leaving groups, and large halogens are better leaving groups than small halogens. what is the order of weak bases that are good LG from largest to smallest ?
c. λ= v/f = 350/0.25m = 1400m L= λn/2 = (1400)(1)/2= 700 m figure 1: 700m = 0.25mm.
The earliest stethoscope was simply a wooden pipe open at both ends. The fundamental frequency of a 0.25-m stethoscope will cause resonance at approximately what distance along the basilar membrane from its base? (Note: Use 350 m/s for the speed of sound in air.) A. 7 mm B. 16 mm C. 25 mm D. 32 mm
C. conc ratio= stock/standard = 0.001/0.0001= 1.0 x 10^1
The passage states that the MgO standard solutions were prepared for analysis by diluting small portions of the 0.001 M MgO stock solution. Compared to the concentration of the MgO stock solution, the concentration of the MgO standard solution with the lowest nonzero absorbance is how many times smaller? A. 1 × 10^−7 B. 1 × 10^−1 C. 1 × 10^1 D. 1 × 10^2
B. 9 x 10^-3 L (0.1 mol/1 L) (1 mol/ 1 mol)= 9 x 10^-4 9 x 10^-4 mole x 6.02 x 10^23 = 5 x 10^20
The students prepared unknown Samples 1 and 2 by mixing 25 mL of reservoir water, 16 mL of 2% HNO3, and 9 mL of 0.1 M LaCl3 for a total sample volume of 50 mL each. The samples were each tested three times using flame AA spectroscopy, yielding the results reported in Table 1. Approximately how many La3+ ions are present in each of the unknown samples? A. 1 × 10^−27 B. 5 × 10^20 C. 9 × 10^20 D. 6 × 10^22
Row/Period/Series Horizontal
They have the same number of electron shells. They are arranged on the basis of similar chemical properties and physical properties.
DNA replication within a eukaryotic cell is regulated by several key enzymes
Topoisomerase introduces negative supercoiling in the DNA double helix ahead of the replication fork to reduce the strain produced by unwinding, which causes positive supercoiling. DNA helicase unwinds the DNA double helix and separates the parent strands at the origin of replication. Single-stranded DNA-binding protein binds to each strand to prevent spontaneous reannealing of unwound single-stranded DNA. Primase synthesizes RNA primers and positions them at the beginning of each DNA strand. Only one primer is needed for leading strand synthesis, but lagging strand synthesis requires many RNA primers. DNA polymerase synthesizes daughter strands in a 5′ → 3′ direction only. One daughter strand is synthesized continuously toward the replication fork (leading strand); the other strand is synthesized discontinuously in a direction away from the replication fork (lagging strand), with more and more segments added as the replication fork progresses. This process results in the formation of Okazaki fragments, short stretches of newly synthesized DNA separated by RNA primers. DNA ligase joins Okazaki fragments.
C. pKa of NH3= 9 pKa of COOH=2 pH> pKA = - pH < pKA = +
What will be the net charge of the majority of L-phosphotyrosine molecules when placed in an aqueous solution at pH 8.0? (Note: The pKa values of the phosphate group are 2.2 and 7.2.) A. 0 B. −1 C. −2 D. −3
D. When sound crosses from one medium to another, a portion of the wave's energy is reflected. Therefore, sound waves lose energy (are attenuated) and their intensity decreases when passing from air to a solid structure. When a wave moves from one medium to another, its frequency does not change. Changes in wave velocity only cause the wavelength to change. The propagation velocity of sound waves depends on the properties of the medium: Velocity increases with temperature. Velocity is slowest in gases, faster in liquids, and fastest in solids. Within a phase of matter, velocity increases with stiffness and decreases with density. Therefore, when sound passes from air to a solid (such as the tympanic membrane), its propagation velocity increases.
When sound passes from air to the tympanic membrane, what changes occur to the sound's intensity and velocity? A. Both increase B. Both decrease C. Intensity increases; velocity decreases D. Intensity decreases; velocity increases
A. Ketones and aldehydes undergo acid-catalyzed addition of 1° and 2° amines to form imines or enamines, respectively. Like ketones and aldehydes, imines contain a carbon-heteroatom double bond (nitrogen in imines, oxygen in ketones and aldehydes). Enamines are the nitrogen analogue to enols, containing a carbon-carbon double bond.
Which neutrally charged functional group forms in an acid-catalyzed reaction between a secondary amine and a ketone? A. Enamine B. Nitrile C. Imine D. Alkene
B. Bottleneck events reduce genetic diversity and change the allele frequencies of a population in a random way. For example, an allele can be eliminated completely from the gene pool if no members carrying that allele survive. Likewise, rare mutant alleles can become more prevalent than wild-type alleles if most members carrying the mutant allele survive and most members carrying the wild-type allele do not. Because deleterious (ie, harmful) mutations are most likely selected against, which keeps the population of individuals with such mutations low, only large environmental changes like a bottleneck event may allow a deleterious mutant allele (eg, in the shaded mitochondria) to become more prevalent in the population than the wild-type allele (eg, in the nonshaded mitochondria)
Which of the following events most likely occurred between Generation 1 and Generation 2? Note that the shaded allele is the result of a substitution mutation and is considered to be a deleterious allele in both generations. A. Meiosis B. Population bottleneck C. Natural selection D. New mutation
D. Catalytic turnover refers to the rate at which an enzyme-bound substrate is converted to product. It is given by the rate constant kcat and is proportional to the maximum reaction rate Vmax. On a Michaelis-Menten plot, catalytic turnover is reflected in the height of the plateau that occurs at high substrate concentrations. A high kcat (or a high plateau) corresponds to high catalytic turnover. Catalytic efficiency is defined by the ratio kcat/Km and is a measure of enzyme specificity. It indicates the rate of catalysis at low substrate concentrations and is proportional to the initial slope of the Michaelis-Menten plot. An enzyme that quickly creates product at low substrate concentrations (high initial slope) is said to be catalytically efficient because only a small amount of substrate is needed to generate substantial activity. A high kcat, a low Km, or both may contribute to catalytic efficiency.
Which of the following substrates yields the most optimal catalytic turnover and catalytic efficiency, respectively? A. CSL-173 and WKLL-ACC B. WKLL-ACC and CSL-176 C. CSL-176 and CSL-173 D. CSL-173 and CSL-176
B. Paragraph 1 in the passage states that BLM may be involved in DNA synthesis repair of stalled replication forks during replication stress (arrest). Although all the peptides obtained from the database can likely repair stalled replication forks, the recQ found in Escherichia coli (ie, the bacterial species) is the only option that would be required to repair stalled replication forks at only one origin of replication in vivo. This is because prokaryotes have circular DNA with a single origin of replication (Ori) in the cytoplasm, whereas eukaryotes have linear DNA with multiple origins of replicationin the nucleus. Therefore, a single E. coli bacterium would have circular DNA and a single origin of replication containing two replication forks, which would be repaired by recQ in the setting of replication stress. Prokaryotes typically have circular DNA with a single OIR in the cytoplasm (
Which statement most likely explains the role of these peptides during replicative stress in the organisms studied? A. SGS1 would be required to repair replication forks in vivo at one origin of replication. B. recQ would be required to repair replication forks in vivo at one origin of replication. C. BLM would be unable to repair replication forks in vivo at multiple origins of replication. D. RECQL would be unable to repair replication forks in vivo at multiple origins of replication.
affected father
X-linked dominant inheritance all daughters are affected all sons are unaffected
affected mother
X-linked dominant inheritance all sons and daughters have 50% chance of being affected
C. For radioactive particles, the half-life t 1/2 is the amount of time needed for half the quantity of a substance to decay. The fraction remaining after a number of half-lives can be calculated using a formula for exponential decay, 1/2^n, where n is the number of elapsed half-lives.
Yttrium-90 (90Y) is a radiopharmaceutical agent used to treat overgrown joint lining known as pigmented villonodular synovitis, as well as some forms of liver cancer. It has a half-life of about 64 hours. A patient is injected with 20 ng of 90^Y. Assuming the yttrium is not excreted, how long will it take for the initial amount of 90^Y to be reduced to 2.5 ng? A. 64 hours B. 128 hours C. 192 hours D. 256 hours
histone
__________are proteins that bind DNA through electrostatic interactions between the negatively charged DNA backbone and positively charged histone residues like lysine. Modifications that remove the positive charge (on Lys of histone tail) loosen the DNA-_______ interaction and lead to an upregulation of gene expression.
Schiff bases
are commonly seen in biochemistry as imine linkages between a protein and a substrate or a prosthetic group. _______________ are formed between a primary amine (eg, of a lysine side chain) and a carbonyl compound. _______ formation involves the aldehyde group of retinal being attacked by a nucleophilic primary amine from an amino acid side chain. results in an imine
A. Decarboxylation is a reaction that removes a carboxyl group from a carboxylic acid with a β-carbonyl, releasing the carboxyl group as CO2 gas. An ester with a β-carbonyl can also undergo decarboxylation if the ester is first hydrolyzed to a carboxylic acid. Once the carboxylic acid is formed, decarboxylation occurs through a cyclic transition state that incorporates both carbonyls, releases CO2, and forms an enol. The enol tautomerizes to the keto form, or the α-carbon can be alkylated. Esters with a β-carbonyl can also undergo decarboxylation if they are hydrolyzed to a carboxylic acid first.
compound 1, a carboxylic acid derivative, is shown above. The carboxylic acid it is derived from cannot undergo decarboxylation because Compound 1: A. does not contain a β-carbonyl. B. contains a conjugated ester. C. contains a β-diketone. D. does not contain an acidic proton.
I = Q/t = V/R
current equals _______?
conformational isomers
differ by rotation around a single sigma bond
L= λn/2 (n=1, 2, 3,4..)
equation for both open ends?
L= λn/4 (n= odd only)
equation for one open end in a pipe?
condensation
gas to liquid
microtubules
hollow tubes made of protein that help cells move material around itself and resist compression also make up the structural elements of flagella and cilia, which are used to help move the entire cell or substances along the outer surface of the cell.
temperature
is a measurement of the average kinetic energy of the molecules in a substance. That is, the molecules of a substance at 10 K are moving slower than those of a substance at 20 K. 0 Kelvin is the theoretical temperature where the atoms in a substance would be perfectly still (ie: they have no energy). KE_avg = 3/2(kT), where k is Boltzman's constant
distillation
is a technique used to separate liquid molecules based on their boiling points. The compound with the lowest boiling point evaporates first. The mixture is heated slowly so that the boiling temperatures of compounds with higher boiling points are not reached before the compound with a lower boiling point (distillate) evaporates and is collected. The vapors of the distillate travel up the distillation column connected to a thermometer and a condenser and then condense into the receiving flask, which is in an ice bath to prevent the distillate from evaporating.
condensation rxn
is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water, ethanol, or ammonia. If water is lost, the reaction is also known as a dehydration synthesis. exmp: DNA. synthesis
calcitonin CalcitonIN: brings Ca2+ into bones.
is secreted in response to a high blood calcium level and decreases osteoclast activity, ultimately decreasing blood calcium.
PTH ParathyROID: RIDS bones of Ca2+
is secreted in response to a low blood calcium level and stimulates bone resorption by osteoclasts, causing an increase in blood calcium.
mtDNA
is subjected to high levels of oxidative stress: The respiratory chain is the major source of reactive oxygen species in the cell, meaning that the mtDNA is subject to high levels of oxidative stress. This has lead to a theory that accumulating mitochondrial damage due to oxidative stress progressively decreases ATP production, thereby causing aging. The mitochondrial DNA contains only 37 genes, but, unlike the nuclear DNA, it contains very little noncoding DNA and therefore has much higher gene density than nuclear DNA. There are no introns. Of these 37 genes: 22 code for tRNA. 2 code for rRNA. 13 code for proteins It is small, circular, double-stranded, and doesn't use histones. It codes for tRNA, rRNA, and only 13 proteins. It contains no introns and very little non-coding DNA. the heavy strand encodes for most Maternally inherited only
Heat
is the TRANSFER of energy from a substance with higher energy to a substance of lower energy. This is why the formula Q=mc(delta)T has the change in temperature. Because there is a transfer of energy involved. Imagine you had some object that was extremely hot (high in energy), but was somehow isolated from all other objects. That object does not have heat in and of itself. Heat, in the physics/chemistry sense, is specifically the transfer of energy, even though in casual language people tend to misuse this term. Kinetic energy is energy something has be being in motion. KE=(1/2)mv^2. If you transfer heat to something, you are raising its internal amount of energy, or the average kinetic energy of its molecules. Since the mass of the molecules isn't changing, this simply means you are making them move with a higher velocity. Because temperature is a measure of average kinetic energy, this means the temperature is rising. One caveat is when you have a substance changing from liquid to gas, like boiling water. If you continue to add heat to water (or any liquid which can vaporize), its temperature will rise until it reaches its boiling point. It will then vaporize without increasing in temperature anymore.
B-oxidation
is the repetitive four-step pathway that breaks down fatty acyl-CoA molecules two carbons at a time to form acetyl-CoA molecules, which can subsequently enter the citric acid cycle. The oxidation of a saturated acyl-CoA proceeds according to the following steps: 1. Oxidation of the C2-C3 bond of acyl-CoA by the enzyme acyl-CoA dehydrogenase, forming the α,β-unsaturated trans-enoyl-CoA. FAD is used as an oxidizing agent and is reduced to produce FADH2. 2. Hydration across the double bond by the enzyme enoyl-CoA hydratase. The hydration reaction stereospecifically adds the hydroxyl group to C3, the β-carbon, forming β-hydroxyacyl-CoA. 3. Oxidation of the hydroxyl group by the enzyme β-hydroxyacyl-CoA dehydrogenase. NAD+ is used as the oxidizing agent, producing NADH + H+ and a β-ketoacyl-CoA. The four-carbon β-ketoacyl-CoA formed during the final round of β-oxidation is commonly called acetoacetyl-CoA, which serves as a precursor molecule in ketone body synthesis and cholesterol synthesis. 4. Cleavage of the α-β bond by free coenzyme A, catalyzed by the enzyme acetyl-CoA acyltransferase. C1 and the α-carbon leave as acetyl-CoA, and the oxidized β-carbon is now C1 of the shortened acyl-CoA chain. This reaction is reversible and can also produce acetoacetyl-CoA from two acetyl-CoA molecules during ketone body or cholesterol synthesis.
vaporization
liquid to gas
intermembrane space of mitochondria
low pH= High proton concentration
eukaryotes human (eukaryotic) genes with conserved DNA helicase activity that would likely be found to repair replication forks at the multiple replication origins present in a eukaryotic organism. The eukaryotic genome is significantly larger and more complex than the prokaryotic genome. Therefore, simultaneous replication at multiple origins allows the large eukaryotic genome to be copied in a rapid and effective manner despite its size.
multiple origins of replication and linear DNA An origin of replication expands to form a replication bubble, which contains two replication forks that move apart in opposite directions during DNA synthesis.
Net ATP for beta oxidation
n= # of carbons in the even numbered saturated, activated fatty acid. n/2= # of acetyl-CoA n/2-1= # of beta oxidation cycles. 1 Acetyl-CoA => 1 TCA cycle => 10 ATP For every 1 B-Oxidation = 1 FADH2. 1 NADH FADH2= 1.5 ATP NADH= 2.5 ATP exmp: n=12 6 Acetyl-CoA. 60 ATP 5 B-Oxidation cycles. 20 ATP NET ATP: 60 + 20 = 80 -2 = 78 ATP (minus 2 from long-chain fatty-acyl-CoA synthetase). TOTAL ATP= 78
node
occur at the locations of zero displacement
antinodes
points of maximum amplitude/displacement on a standing wave
osteoblasts
promote the precipitation of calcium and phosphate from the bloodstream and their transfer and incorporation into the bone matrix. are the cells required for bone synthesis and mineralization, both during the initial formation of bone and during bone remodelling forms new bone tissue
double replacement
reactions between two ionic species, the cations (or anions) of the two compounds simply exchange counter ions, and these exchanges frequently result in the formation of a new insoluble product (seen as a precipitate). exmp: AgNO3 + NaCl -> AgCl + NaNO3
decomposition
reactions follow the pattern of one reactant species breaking down into two or more product species (the opposite pattern of combination reactions). exmp: CaCO3 -> CaO + CO2
combination
reactions follow the pattern of two or more chemical species reacting to combine and form one product species. exmp: 2 Fe + O2 -> 2 FeO
single replacement
reactions involve the reaction of a compound with a free element (a substance in its elemental form that is not bonded with other types of atoms) and the formation of a new compound and a new element as the products. exmp: Zn + 2 HCl -> ZCl2 + H2
heterochromatin (closed)
repetitive DNA transcriptionally inactive methylation is increased histone acetylation decreased
Ligand-gated ion channels
require a ligand to bind before the channel opens. Ligands that bind and activate receptors are also called agonists. Agonists function as allosteric activators of these channels because they bind to an extracellular or intracellular ligand binding site to cause a conformational change that affects the ion gate within the transmembrane domain of the channel.
autosomal recessive inheritance
require the presence of two copies of the defective gene for disease manifestation and show no predilection for males or females. About 25% of children are affected if both parents carry one copy of the defective gene
Mechanically gated ion channels
respond to mechanical forces like pressure or tension. These forces alter the dimensions of the fluid lipid bilayer membrane, and therefore cause conformational changes that result in the opening of the gate.
voltage gated ion channels
respond to prior changes in the membrane potential. Voltage-gated channels have voltage sensors in their transmembrane regions (eg, α-helices rich in positively charged amino acids) that are electrostatically stabilized in a particular conformation at the cell's resting membrane potential. Nearby changes in membrane potential disrupt this stability, causing conformational changes that open the gate and allow the electrical signal to spread.
constitutional (structural) isomers
same molecular formula, different connectivity of atoms
osteoclasts
secrete acid proteolytic enzymes and acid that break down the mineral components of bone, releasing calcium and phosphate into the bloodstream. breaks down old bone tissue (bone-resorbing cells)
euchromatin (open)
single copy DNA transcriptionally active methylation is decreased histone acetylation increased
Fastest in solids, slowest in gases
sound travels fastest in what?
sympathetic nervous system
stimulates glucose release which division of the ANS?
affected father
x-linked recessive inheritance all daughters are carriers all sons are unaffected
carrier mother
x-linked recessive inheritance daughters have 50% chance of becoming carriers sons have 50% chance of being affected.
