AAMC Test100% ACCURATE GRADE A+ GURANTEED QUESTIONS and ANSWERS

For a thermodynamic mixture of isomeric products the relative mole ratio of products is directly related to the relative stability of these products #2. What can be inferred from the results of scheme A about the relative thermodynamic stabilities of Compounds 4a and 4b A. Compound 4a is less stable than Compound 4b. B. They are equally stable. C. Nothing can be inferred about relative thermodynamic stabilities. D. Compound 4a is more stable than Compound 4b. Compound 4a is more stable than 4b The image shows that 4a is produced 60% and 4b 40%. --So 4a will be more stable among the two thermodynamic products #3. Which of the following compounds is most likely to be a major product in step 2 if the aldol condensation is NOT followed by a dehydration reaction? Ans in image --coz if there is no dehydration, then the OH would be present instead of the double bond #4. Compound X is shown below.(image) If compound 2 is replaced with compound X, what will be the structure of the final product in steps 1 and 2? (Note: assume that the yields of steps 1 and 2 are not affected by substitution) Ans in image --coz this is the product of Michael addition followed by intramolecular aldol condensation (Robinson annulation) #5. What is the total amount of charge and energy, respectively, that the capacitor will store if it is connected to the battery on the railcar? 1.20C and 7.20J C=Q/V Energy stored by a capacitor = Ue = (1//2)CV^2 = (1/2)QV = (1/2)Q^2V Given V= 12V C = 100 x 10^-3 F Q = VC = (12)(100 x 10^-3) = 1.20 C Ue = (1/2)QV = (1/2)(1.20)(12) = 7.20J #6. Suppose that the railcar passes by a horn that is emitting a sound with a frequency f. Which of the following describes f' that the person on the railcar hears? f' > f before passing the horn, f' < f after passing it Due to doppler effect, the frequency that the person on the railcar hears before passing the horn is larger than the actual frequency of the sound emitted, while the person hears a frequency lower than the actual frequency after passing the horn --Before passing the horn, the object(rail car) is coming closer to the source (horn) so f'>f --After passing the horn, the object(railcar) is moving away from the source (horn) so f<f' Doppler effect The apparent frequency (f') of the source is increased as the source approaches the observer, and is decreased as the sources leaves the observer f' = ((V+_ Vo)/(V-+Vs))f #7. A railcar has a decelerating force of 1000 N. if no braking occurs, a total of how much power would be required to keep the railcar moving at 40 m/s? A. 16 kW B. 40 kW C. 600 kW D. 800 kW Power = work done/ time Work done = Fd v= d/t --> d =vt W= Fd --> Fvt P = Fv = (1000N)(40) = 40000 W = 40 kW There are lot of force values given in the passage but we use 1000N coz the power required must match the work done by the friction force that tends to slow down the railcar #10. Raadioactive tritium (3H) labeleed guanine has been used to measure the rate of biochemical processes that involve its building or incorporation Given that water is the solvent for this type of experiment, what is the best site for tritum labeling? I Because the best site for tritium labeling would not exchange the tritium ions for protons in water. All of the N-H sites (II-IV) would readily exchange tritium protons due to their lone pair-facilitating protonation and subsequent tritium exchange with water, but the C-H site (I), lacking a lone pair, would retain its tritium label #8. If a generator-brake system alone were engaged when the railcar was moving, which of the following graphs would most accurately represent the subsequent speed of the railcar? Ans Image--> Coz the speed of the car decreases in time such that the decelerating force declines linearly with speed, according to the passage. Because the decelerating force is directly proportional to the deceleration acceleration, it follows that the decelerating acceleration itself declines linearly with speed. Finally, because the decelerating acceleration is the rate of change of velocity, or the slope of the velocity vs. time graph, then the slope of the graph must decrease in time #9. The relative thermodynamic stability of isomeric organic compounds can be inferred from which of the following types of experimental data? A. Boiling points B. UV-visible absorption spectra C. Mass spectroscopic fragmentation patterns D. Heats of combustion D. Heats of combustion The relative thermodynamic stability of isomers can be determined based on the amount of heat produced when the compounds are combusted; less heat, greater stability #14. The energy of activation for the reaction described in the passage is given by the energy of: The activated complex minus the energy of the reactants The activation energy for the reaction presents the minimum energy barrier necessary to be overcome by the reactants on the path to products #16. What type of reaction is occurring between I2 and Zn? Oxidation-reduction because both Zn and I2 change oxidation states during the reaction #18. What is the period of the voltage source that operates the plasma pencil? 1000ns Because the period of a time-varying signal is the shortest repitition time. According to fig 2, each pulse is on for 500ns, then off for 500ns. Thus the time between consecutive pulse is 500ns + 500ns = 1000ns #19. What is the maximum energy of the UV photons generated by this plasma pencil? (Note: speed of light is c = 3.0 x 10^8 m/s; Planck's constant is h = 6.63 x 10^-34 J.s) lamda = 200-300n E=hf = hc/lamda given: lamda = 200-300nm the question is asking for MAXIMUM energy, so you would want to minimize the denominator, so use 200nm for lamda E = (6.63 x 10^-34 J.s)( 3.0 x 10^8 m/s)/ (200 x 10^-9 m) = 1 x 10^-18 #20. That the electric field is uniform between the electrodes means that the electric field lines: a) are more closely spaced to the positive electrode than at the negative one b)intersect halfway between the electrodes c) are more closely spaced at the negative electrode than at the positive one d) are equally spaced at both electrodes between them are equally spaced at both electrodes and between them --By definition, electric field lines are spaced in a uniform field #23. the glucose meter measures the current produced during reaction 3. If 0.67 umol of electrons were measured, what mass of glucose was present in the sample. Note the molar mass of glucose is 180 g/mol or 180 ug/umol a) 20 ug b) 60 ug c) 90 ug d) 270 ug B the device measured 0.67 or 2/3 of the electrons. which means that 1/3 of the electrons were consumed. thus, that means that 1/3 of 180. which is 60 ug #24. What additional substance is necessary for reaction 2 to take place? A. FAD B. NADH C. H2O D. Acetyl-CoA FAD --Because among the choices listed, only FAD is a cofactor oxidant What is one characteristic of steroid FOUR FUSED RINGS #26. The pH of a 1L phosphate buffer solution was measured as 7.6, but the experimental procedure calls for a pH 7.2 buffer. Which method will adjust the solution to the proper pH? (Note: pKa values for phosphoric acid are 2.2, 7.2, and 12.3.) A, Add enough 1M Na2HPO3 to increase the phosphate anion concentration ten-fold B. Add 1M NaOH to neutralize a portion of the hydronium ions found in the solution C. Alter the ratio of the monosodium/disodium phosphate added to favor the monosodium species D. All 100mL distilled, deionized water to dilute the basicity of the buffer Alter the ratio of monosodium/disodium phosphate added to favor the monosodium species because in order to lower the pH of a buffer, the proportion of acidic buffer component must be increased. Adding strong base, diluting with water, or adding a different salt will NOT lower the pH #27. When two amino acids are joined via a peptide bond, what is the mass of the byproduct of the reaction? 18amu Peptide bond formation is the dehydration reaction so byproduct will be water #28. Which experimental condition is NOT necessary to achieve reliable data for Michaelis-Menten enzyme kinetics? A. Initial velocity is measure under steady state conditions B. Solution pH remains constant at all substrate concentrations C. The concentration of enzymes is lower than that of substrate D. The reaction is allowed to reach equilibrium before measurements are taken. The reaction is allowed to reach equilibrium before measurements are taken Because once the reaction reached equilibrium, it will be impossible and the kinetic data will look the same regardless of substrate concentration What structure is attached during acetylation? RC=O What is the structure of a hydroxylamine? NHOH #30. What is the general structure of hydroxamic acid? Ans--> image Becuase a hydroxamic acid was described in the passage as resulting from the acetylation (attachment RC=O) of the hydroxylamine nitrogen (NHOH) in compound 2 What coordinates with cations LEWIS BASES!! #38. Which structure represents a component of the HRP cofactor? Ans image --> Because the cofactor is heme, which is a porphyrin. The basic unit of a porphyrin is the pyrrole ring -a 5 sided heterocycle containing one nitrogen atom Resistivity = Inverse of conductivity the best performing PANI had a maximum conductivity of 5x10^-3 Ohm xcm^-1. what is the resistivity of the best performing PANI? a) 0.002 b) 50 c) 200 d) 500 200 1/(5x10^-3) #40. In mammalian cells, iMs have been shown be subject to two epigenetic modifications: methylation and hydroxymethylation. Which two classes of enzymes are needed in the two-step conversion of cytosine to 5hmC? a) transferase and oxireductase b) hydrolase and ligase c) oxidoreductase and hydrolase d) transferase and ligase Transferase and oxireductase --Because the first step involves transfer of a methyl group to cytosine, and the next step involves the hydroxylation of that methyl group. Therefore, the two classes of enzymes needed are a transferase and an oxireductase. #41. What is the correct expression for the deltaG'o for the transition observed in the experiments described in the passage? the products in this passage are the unfolded version of the proteins deltaG'o = -RTlnKeq delta G= -RT lb K (unfolded/native) Keq = [products]/[reactants] #42. Which statement about the unfolding cooperativity and pK of the oligonucleotides is consistent with the data in Figure 1? The oligonucleotides with the lowest pK displays the highest unfolding cooperativity --because the pK is the pH at which the fraction of folded DNA is 0.5. this occurs at the lowest value in 5hmC-WT. Cooperativity is measured as the slope of the unfolding transition. This is also highest in 5hmC-WT.CONTINUED