C/P Section
What was the pH of the unknown aqueous solution? A.4 B.5 C.9 D.10
B. It gave you the concentration PH = -log[H+] 1x10^-5 = 5
What is the closest distance the electrodes used in an NCV test can be placed on a nerve in order to measure the voltage change as a response to the stimulus? A.0.01 m B.0.1 m C.1.0 m D.10 m
B. 0.1 m V*t = D 100 m/s (1 mm/s) = D Convert to meters.. divide by 1000
Suppose that at the end of Reaction 1 the level of the aqueous solution were 26 cm higher inside the buret than outside. Compared to ambient pressure, the pressure of the gas inside the buret would be: A.lower. B.the same. C.2 times greater. D.26 times greater.
I picked D. I wasn't sure how to answer this. Answer is A. The answer is A because the level of the liquid inside is higher than outside which results from the fact that the air pressure outside is higher than the pressure inside. Fluid inside is higher, pressure is lower. Fluid outside is lower, pressure is higher. Inverse relationship.
Metal ions present in plasma are expected to: A.increase the amount of CPFX bound to BSA. B.decrease the amount of CPFX bound to BSA. C.decrease the amount of free CPFX found in plasma. D.have little effect on the amount of bound CPFX.
I put A. The answer is B. I thought it increased, but it is the opposite. The metal ions used in the study reduced the binding based on Kia/K0 data. Lower Ka = more = decrease?
Based on the data in Table 1, the binding site of CPFX on BSA was determined to be: A.primarily at Site II. B.equally partitioned between Site I and Site II. C.primarily at Site I. D.at a site distinct from either Site I or Site II.
I put A. The answer is C. Warfarin competes more and it associates at Site 1. So the biding site is Site 1.
The stabilization of pantothenate in PanK3 is most likely due to an active site: A.arginine. B.asparagine. C.aspartate. D.glutamine.
I put A. The answer is C. Only aspirate has a carboxylate side chain.
One method of isolating polypeptides and proteins from aqueous extracts is freeze drying. The aqueous solution of the polypeptide or protein is frozen. What procedure can be used to remove the water from the frozen sample? A.Sublimation under reduced pressure B.Distillation using steam C.Extraction with organic solvent D.Addition of magnesium sulfate
I put B. Answer is A. I initially put A, but I thought that didn't make any sense because I thought the solid was going into liquid. But now I realize freeze drying = you're freezing the gas into solid, which means that it is sublimation. The only obvious answer is A. Read the question more clearly. JFDDHJHD THIS IS SUCH A STUPID QUESTION TO GET WRONG PLS READ THE QUESTIONS MORE CARFULLY.
Mevalonate exists in equilibrium with Compound X in aqueous solution. What is the structure of Compound X? A.CP-9-1-202CP_72160-Q04a.gif B.CP-9-1-202CP_72160-Q04b.gif C.CP-9-1-202CP_72160-Q04c.gif D.CP-9-1-202CP_72160-Q04d.gif
I put B. Answer is A. Since mevalonic acid contains -CO2H and -OH groups, the open chain acid in aqueous solution will be in equilibrium with the corresponding cyclic ester. 6 membered ring is more thermodynamically favorable than a 4 membered ring
What information about an axon is required to calculate the current associated with an NCV pulse? A.Conductivity, resistivity, and length B.Potential, conductivity, and radius C.Potential, resistivity, and radius D.Potential, resistance per unit length, and length
I put B. Answer is D. I = V/R To determine R, the resistance per unit length, the length, and the potential V are needed. I thought the question was asking for the equation for current, but it is asking how to find the missing variable that we need to find current. We have voltage, we don't have resistance. You can also arrive at the formula because D is the only formula that makes sense. The other ones don't seem familiar. I just guessed on this one because I wasn't sure what it was really asking me.
What is the expected 14C labeling pattern found in isopentenyl phosphate produced this way? Labeled carbon atoms should be found at: A.C1, C3, and C4. B.C1, C3, and C5. C.C2, C3, and C5. D.C2, C4, and C5.
I put C. Answer is D. I guessed.
Which naturally occurring biological molecule would be most likely to bind in the same site as ibuprofen? A.Glucose B.ATP C.Glycerol D.Palmitoleic acid
I put C. I guessed. Answer is D. I knew it wasn't going to be ATP because I knew ATP's structure. Answer is D because fatty acids consist of a hydrocarbon tail and a carboxylic acid, which closely resembles ibuprofen. So palmitoleic acid = a fatty acid.
The amino acids Asp6, Asn9, Thr10, His11, and Arg27 are found near the ADP binding site of PanK3. Which two amino acids contribute to the stabilization of ADP binding described in the passage? A.Asn9 and Thr10 B.His11 and Arg27 C.Asp6 and Arg27 D.Asp6 and His11
I put C. I put B at first but I changed it to C. Stop changing your answers!!!!! The answer is B because both His and Arg side chains can carry a positive charge. They would have favorable ionic interactions with the negatively charged phosphates of ADP. His and Arg are the only ones that can form ionic charges with ADP.
Sites I and II are most likely lined with the side chains of which amino acids? A.R and L B.E and Y C.D and E D.D and H
I put C. The answer is A. I guessed on this. The answer is A because sites I and II recognize hydrophobic and an ionic substrates. Positive charged and hydrophobic side chains point into the binding pocket. Arginine and Leucine
During Trial 5, the wire was heated from 293 K to 673 K while V was held constant at 28 V. How did the current through the circuit change during this time? A.It remained constant at 2 A. B.It remained constant at 4.6 A. C.It increased from 2 A to 4.6 A. D.It decreased from 4.6 A to 2 A.
I put C. The answer is D. It decreases because increasing the heat increases the resistivity. If you increase resistivity, there is less current. Just remember the relationship and this question will be easy.
The unknown compound was probably a: A.weak base. B.strong base. C.weak acid. D.strong acid.
I put D. Strong acid. The answer is C. Weak acid. "The compound dissolved in water and weakly conducted electricity." I put strong acid because it said it completely dissolved. I didn't pay attention to the weakly conducted electricity part. Strong acids are good conductors. Therefore, the compound is a weak acid. The hydrogen ion concentration Ksp for the solution is GREATER than 1x10^-7 (1x10^-5). The compound only partially ionized to form H ions and is a weak acid. Large KSP, small pka = strong acid
The average human body contains approximately 5 liters of blood. If the blood has a density of 1060 kg/m3, what is the total mass of blood in the average human? (Note: 1 L = 1000 cm3.) A.0.212 kg B.0.530 kg C.5.30 kg D.10.6 kg
D = mass over volume Manipulate the formula. Answer is B.
How should the ideal gas equation be rearranged to most easily use the values from the experiment in the passage to calculate the gas constant? A.PV = nRT B.R = nPT/V C.nR = PV/T D.R = PV/nT
D. Was confusing at first, but I reread the passage and it said the gas constant is R.
What are the components that comprise Coenzyme A (Figure 1)? A.β-Mercaptoethylamine, phosphopantothenate, dAMP with additional 3′-phosphate B.β-Mercaptopropylamine, pantothenate, AMP with additional 5′-phosphate C.β-Mercaptopropylamine, phosphopantothenate, dAMP with additional 5′-phosphate D.β-Mercaptoethylamine, pantothenate, ADP with additional 3′-phosphate
D. ADP. I know the structure for ATP, and ADP has one less phosphate group. That is what was in the compound so D is the answer.
Researchers used reverse-phase high performance liquid chromatography (HPLC) (polar mobile phase and non-polar stationary phase) to separate Compound 2 from Compound 1. Which statement accurately describes this process? A.Increasing the polarity of the mobile phase will decrease the retention time of Compound 1 relative to Compound 2. B.Compound 1 will elute first because it is more polar than Compound 2. C.Decreasing the affinity of Compound 1 for the stationary phase will increase its retention time relative to Compound 2. D.Compound 2 will elute first because it does not interact as favorably with the stationary phase as Compound 1.
D. Compound 2 is more polar than Compound 1 due to methyl hydroxylation. In RP-HPLC, the more polar compound will elute first.
The peptide bond between which two amino acid residues is cleaved by HIV protease? A.Phe and Ala B.Pro and Val C.Val and Ala D.Phe and Pro
D. HIV protease (or any aspertic protease) cleaves at C terminal of Phe and Pho Check your biochem notes.
Two additional compounds were studied: NO2(OH) dissolved in water and produced an acidic solution, and Ni(OH)2 dissolved only in an acidic solution. What type of compounds were these? A.Both were oxyacids. B.Both were bases. C.NO2(OH) was a base and Ni(OH)2 was an oxyacid. D.NO2(OH) was an oxyacid and Ni(OH)2 was a base.
D. HNO3 dissolves to generate an acidic solution, the bond between O and H in the structural formula NO2OH breaks when the substance dissolves, making it an oxyacetylene. The latter substance, is insoluble in neutral water, but will dissolve if the solution is acidic. This behavior is typical of substances that feature basic anions. The bond between Ni and O is the one that breaks when Ni(OH)2 dissolves.
During glycolysis, pyruvate CH3C(=O)CO2- is reduced to lactate CH3CH(OH)CO2- by nicotinamide adenine dinucleotide (NADH). What is the balanced reaction for this conversion? A.CH3C(=O)CO2- + 2NADH → CH3CH(OH)CO2- + 2NAD+ B.CH3C(=O)CO2- + 2NADH + 2H+ → CH3CH(OH)CO2- + 2NAD+ C.CH3C(=O)CO2- + NADH + 2H+ → CH3CH(OH)CO2- + NAD+ D.CH3C(=O)CO2- + NADH + H+ → CH3CH(OH)CO2- + NAD+
D. I just made sure the equation is balanced.
An object with a mass of 0.1 kg absorbs 250 J of heat while changing temperature from 20°C to 25°C. What is the specific heat of the object? A.125 J/(kg·°C) B.250 J/(kg·°C) C.375 J/(kg·°C) D.500 J/(kg·°C)
D. Q=mcat
Addition of which disaccharide to a solution of Ag2O in NH3(aq) will NOT result in the deposition of shiny silver mirror on the walls of the reaction vessel?
D. Sucrose I picked this because it was the only different one out of all the choices. The other choices ere too similar. AAMC says that the answer is D because sucrose does NOT posses a hemiacetal functional group, will NOT undergo mute rotation, and will NOT be oxidized by Ag+ Sugars that are called reducing sugars are saccharides that undergo mustaotation and are capable of ring-opening. Ring-opening occurs at a hemiacetal group and the intermediate is an aldehyde.
What is the concentration of Cl- ions in a 0.1 M solution of calcium chloride? A.0.02 M B.0.05 M C.0.10 M D.0.20 M
D. The formula for calcium chloride is CaCl2 and it produces twice as many Cl- ions as Ca2+ ions. What I did was equal two formulas to each other of Molarity, with the same volume. mol/M = mol/M and solved for the M of Cl-
If the data used to generate the kinetic parameters in Table 1 were displayed in a Lineweaver-Burk plot, the plot would show that the y-intercept: A.is the same for all three variants. B.is the same for CYP2C9*1 and CYP2C9*2 but different for CYP2C9*3. C.is the same for CYP2C9*2 and CYP2C9*3 but different for CYP2C*1. D.is different for all three variants.
D. Y-intercept is the inverse of Vmax. It's different for all three compounds, so D. Is the answer. Pretty straightforward
The density of a human body can be calculated from its weight in air, Wair, and its weight while submersed in water, Ww. The density of a human body is proportional to: A.Wair/(Wair - Ww). B.(Wair - Ww)/Wair. C.(Wair - Ww)/Ww. D.Ww/(Wair - Ww).
A. The ratio of the density o an object to the density of the fluid it is submersed in is equal to the ratio fo the weight of the object in air to the different of submersed weight and weight in air.
What is the fate of the NADH used in the assay described in the passage? A.Oxidation of NADH to NAD+ B.Reduction of NADH to NAD+ C.Oxidation of NAD+ to NADH D.Reduction of NAD+ to NADH
A.
One function of the myelin sheath is to: A.insulate the axon from the surroundings. B.decrease the radius of the axon. C.produce Schwann cells. D.increase the capacitance of the axon.
A. Easy The purpose of myelin sheath is to assist with the propagation of nerve impulses. It functions in this capacity by insulating the internal cytoskeleton from the extracellular fluid. When the nodes of Ranvier open in response to stimulus, the resulting depolarization can only be transmitted along the axon since the myelin sheath is insulating.
Although highly toxic, amygdalin has been investigated as a potential anti-cancer compound. When refluxed in H2SO4(aq), amygdalin breaks down to produce glucose (2 equivalents), HCN (1 equivalent), and benzaldehyde (C6H5CHO, 1 equivalent). Which structure most likely corresponds to amygdalin?
A. I answered this by looking at the formula they gave me and counting the carbons for the benzaledehyde. A was the only one that made sense.
Which of the following graphs best illustrates the relationship between T and R?
A. Linear graph. T and R are linearly propitiate.
Based on the information in Figure 2, what is the half-life of 99mTc? A.6 h B.12 h C.18 h D.24 h
A. Look at the graph.
What is the work done by the patient during a 3-minute exercise on the bicycle? A.5400 J B.90 J C.6 J D.0.16 J
A. Power = w/t (watts) Work = F* d (joules)
What is the minimum amount of heat energy required to increase T from 373 K to 573 K? (Note: The specific heat capacity of iron is 460 J/kg·K.) A.368 J B.550 J C.1840 J D.3680 J
A. Q=MCAT
Which substance is NOT a product of squalene metabolism? A.Glucose B.Testosterone C.Cholesterol D.Cortisone
A. Squalene forms steroids
What type of reaction is Reaction 1? A.Oxidation/reduction B.Lewis acid/Lewis base C.Double replacement D.Ionization 2HCl(aq) + Mg(s) → MgCl2(aq) + H2(g)
A. The others really don't make sense.
The principal quantum number is a measure of which of the following? A.Approximate radial size of an electron cloud B.Approximate shape of an electron cloud C.Number of valence electrons that orbit a nucleus D.Number of protons and neutrons found in the nucleus of an atom
A. The principle quantum number (n) is most closely associated with the potential energy of an electron.
Mevalonate (Compound 2, Reaction 3) is expected to display prominent absorption in which region(s) of its infrared spectrum? 3200-3500 cm-1 1700-1750 cm-1 1580-1610 cm-1 A.II only B.I and II only C.II and III only D.I, II, and III
Answer is B. The answer to this item is B because mevalonic acid contains both -CO2H and -OH groups, but does not contain a conjugated or aromatic C=C bond. The carboxyl group C=O stretching frequency falls in the region 1700-1750 cm-1, whereas the O-H stretching frequency is expected to fall in the region 3200-3500 cm-1. This question requires Scientific Reasoning and Problem Solving to arrive at the answer.
An ultrasound examination could show the motion of a fetus. In order to image this motion, the ultrasound examination devices requires what minimal information? A.The speeds of the sound and of the moving object. B.The speed of the sound, and the frequencies of the sound waves emitted and observed. C.The speeds of the sound and of the moving object, and the frequencies of the sound waves emitted and observed. D.The speeds of the sound and of the moving object, and the frequencies and wavelengths of the sound waves emitted and observed.
Answer is B. I thought it was C at first, but the Doppler effect doesn't need the speed of the moving object, just the speed of sound. The Doppler effect is used with ultrasound waves to provide fetal images. The Doppler effect relates the frequency of the ultrasound wave as detected by a moving detector the the frequency of the wave when the source is stationary, speed of the source, and the speed of the detector.
What factor explains how a single stereoisomer is formed in Reaction 2? A.One of the reactants is chiral. B.Both reactants are chiral. C.The solvent medium is chiral. D.The enzyme is chiral.
Answer is D. I put A. Neither reactant is chiral. I knew none of the reactants were chiral, I didn't think it was possible for the enzyme to change chiral centers.
Passage 1 (Questions 1-4) HIV protease is an example of an aspartyl protease; an enzyme that utilizes an aspartate side chain during the catalytic cleavage of a peptide bond. Since HIV protease is a relatively small homodimer of a 99-residue protein, it can be directly synthesized, or cloned and expressed in fast growing cells. For this reason, it was targeted for structure-based drug design in order to treat HIV infection. A portion of the peptide cleaved by HIV protease is shown in Figure 1. CP-9-1-202CP_76320-00-Pi.gif Figure 1 The peptide bond cleaved by HIV protease Using molecular models of the HIV protease enzyme, researchers designed and synthesized transition state analogs. One such molecule is Compound 1, shown in Figure 2, which is a potent HIV protease inhibitor. CP-9-1-202CP_76320-00-Pii.gif Figure 2 Structure of Compound 1 Compound 1 has an in vivo half-life of 1.8 h and is primarily metabolized by CYP3A, an enzyme in the cytochrome P450 family. The major metabolite of Compound 1 results from dealkylation of CH2R groups attached to the piperazine ring system (Reaction 1). CP-9-1-202CP_76320-00-Piii.gif Reaction 1 One of the main side effects of prolonged use of Compound 1 is the formation of kidney stones composed of calcium oxalate CaC2O4. Researchers used their knowledge of the HIV protease active site, and the metabolic pathways that lead to destruction of Compound 1, to design and synthesize several derivatives of Compound 1 in an effort to modify its properties and increase its potency and half-life. Compound 1 is used to treat HIV infection based on its ability to act as: A.an agonist. B.an antagonist. C.a placebo. D.a catalyst.
B. Antagonist Compound 1 binds to the transition state of HIV protease and serves to treat infection. It is clearly inhibiting this enzyme through its binding and thus serves as an antagonist.
What is the frequency of the emitted gamma photons? (Note: Use Planck's constant h = 6.6 x 10-34 Js and the elementary charge e = 1.6 x 10-19 C.) A.2.11 × 1035 Hz B.3.38 × 1019 Hz C.3.01 × 10-20 Hz D.1.45 × 10-47 Hz
B. E = Hf -19+34 = 15. B has the closes to that.
Which data suggest that the differences in Compound 1 metabolism between the variant and wild-type CYP2C9 enzymes are NOT due to changes in the binding affinity toward Compound 1? A.Compound 1 is still eliminated from the body of patients expressing the CYP2C9*3 allele. B.The KM values for the variant enzymes do not differ significantly from the wild-type enzyme. C.The amino acid substitutions at positions 144 and 359 do not change the binding pocket of the variant enzymes. D.The side chains of the amino acid residues at positions 144 and 359 are charged at physiological pH.
B. Km doesn't change. Km is binding affinity.
In this reaction, NADPH functions as: A.an oxidizing agent. B.a reducing agent. C.a catalyst. D.an electrophile.
B. NADH donates an H+, making it oxidized. Because it is being oxidized, it is a reducing agent. It is not an electrophile because it's not going a nucleophilic attack. Not a catalyst because it doesn't change the free energy of the reaction or stabilize the transition state. It's between oxidizing and reducing agent. You should be able to pick the correct answer by knowing that NADH is being OXIDIZED = reducing agent.
Channel X transmits only the smallest substances dissolved in the extracellular fluid through the axon membrane. Which substance does Channel X transmit? A.Proteins B.Sodium ions C.Potassium ions D.Chloride ions
B. Sodium cations are the smallest of the species listed. Use the periodic table and see the mm. Proteins are macro molecular and are much larger than ions!
Which image best illustrates the electric field lines between the inside of an axon and the surrounding extracellular solution?
B. The arrows going from outside of the membrane inside the axon axon <- extracellular fluid Incorrect I put A because I thought the inside of the axon was positive and was moving towards the negative (axon -> ecf) but it is the other way around. It is B because the electric field lines exit from the positive and enter negative charges. The axon is negatively charged. The extracellular solution has a zero net potential. I thought it was the opposite. I guess I thought the image was during the action potential, where the axon is positive. But normally, the cell/axon is more negative than the ECF so the lines would go -> so positive -> negative. ECF is (0), axon is NEGATIVE. <-
The advantage of the Doppler ultrasound technique over the standard ultrasound technique is that it also allows: A.distinguishing between fluids and tissue. B.measuring the blood flow. C.measuring the tissue density. D.measuring the heart wall thickness.
B. The passage is about blood flow.
When choosing a buffer to use for an experiment conducted at pH 5.3, it would be best to choose one with a pKa of: A.2.14. B.4.75. C.6.5. D.7.0.
B. You learned this in biochem
Why do kidney stones form in some individuals treated with Compound 1? A.[Ca2+] + [C2O42-] > Ksp B.[Ca2+][C2O42-] > Ksp C.[Ca2+] + [C2O42-] < Ksp D.[Ca2+][C2O42-] < Ksp
B. [Ca2+][C2O4^2-] precipitates so it exceeds the solubility product constant Ksp.
What is the net charge of both pantothenate and phosphopantothenate in aqueous solution at pH 7? A.0 for pantothenate and 0 for phosphopantothenate B.−1 for pantothenate and −1 for phosphopantothenate C.−1 for pantothenate and −3 for phosphopantothenate D.−3 for pantothenate and −4 for phosphopantothenate
C.
How many stereoisomers of Compound 1 exist? A.8 B.16 C.32 D.64
C. 32 Incorrect!! Didn't count chiral centers properly. Counted 4 not 5. Look more carefully next time. There are 5 chiral centers. 2^5. Equation to use: 2^n.
What is the net charge of the peptide Arg-Ala-Phe-Leu at pH 8? A.-1 B.0 C.+1 D.+2
C. Arginine is the only amino acid here with a charge (+1).
Which of the following statements explains why the boiling point of HF is abnormally high when compared to the boiling points of other Group 7A hydrides? A.The H-F bond is much less polar than the bonds between H and the other halogens. B.HF has the lowest molecular mass of the Group 7A hydrides. C.HF is affected by hydrogen-bonding interactions to a much greater degree than the other Group 7A hydrides. D.HF has the highest vapor pressure among the Group 7A hydrides.
C. H-F has hydrogen bONDING Hydrogen bonding = between N, O, F The other ones don't make any sense. Hydrogen bonding is a higher than anitcipated dipole-dipole interaction, it causes substances that exhibit it to have higher than expected boiling points and lower vapor pressures.
The central atom, A, of the unknown compound was most likely: A.an alkali or alkaline earth metal. B.a transition metal. C.a nonmetal. D.a noble gas.
C. It says it in the passage The compound produces an acidic solution when dissolves. compounds with the general formula AOm(OH)m are acids if A is a non-metal.
Myopia is a condition of the eye where the crystalline lens focuses the light rays to a position between the lens and the retina. To correct for this condition, a thin lens is placed in front of the eye that will help to focus light on the retina. The type of lens required is: A.cylindrical. B.converging. C.diverging. D.spherical.
C. Myopia = nearsightedness = concave = diverging lens = upright, virtual image
Squalene is produced in the human body as a precursor to which important class of compounds? A.Triacyl glycerols B.Phospholipids C.Steroid hormones D.Prostaglandins
C. Steroid hormones Squareness is a precursor for cholesterol. Steroid is made of cholesterol.
The electrically charged particle emitted during the decay of 99Mo is: A.a photon. B.a neutrino. C.an electron. D.a positron.
C. The negative beta particle is the same given to the electron emitted during the nuclear decay of heavy nucleus.
What was the major goal of the experiment in the passage? A.To evaluate the molar mass of H2 gas B.To study the mechanism of Reaction 1 C.To determine the measured variables of the Ideal Gas Law D.To study the reactivity of magnesium with acids
I picked A at first because that was what was measured in the experiment. However, the passage talks about ideal gas law so I changed my answer to C. I guess be careful reading the article.
What is the approximate density of the wire at 473 K? (Note: The volume of the wire is 5 × 10-7 m3.) A.2000 kg/m3 B.3600 kg/m3 C.6400 kg/m3 D.8000 kg/m3
Mass over volume . D.
