AAMC sample test un-scored - chem/phys *Compound 1 is used to treat HIV infection based on its ability
to act as:
A.agonistB.antagonistC. a placeboD. a catalyst correct answersAnswer is B.antagonist An antagonist blocks the biochemical function of the protein it binds to (basically aninhibitor) -> which is what Compound 1 does - it blocks the catalytic activity of HIVprotease towards its substrate ^How many stereoisomers of Compound 1 exist?A.8B.16C.32D. 64 correct answersAnswer is
- 32
Calculate number of stereoisomers by 2^n rule, so
2^5 = 32
^Why do kidney stones form in some individuals treated with Compound 1?
- [Ca2+] + [C2O42-] >
KspB. [Ca2+][C2O42-] > KspC. [Ca2+] + [C2O42-] < KspD. [Ca2+][C2O42-] < Ksp correct answersAnswer is B. [Ca2+] [C2O42-] > Ksp Kidney stones re effectively a precipitate of CaC2O4s) and precipitation occurs whenthe reaction quotient Q exceeds Ksp (the equilibrium constant) - here the reactionquotient Q = [Ca2+]
[C2O42-]
The peptide bond between which two amino acid residues is leaved by HIV
protease:
- Phe and
AlaB. Pro and ValC. Val and AlaD. Phe and Pro correct answersAnswer is D. Phe and Pro 1 / 2
Peptide bond is cleaved between Phenylalanine on the N-side and Proline on the C-sid e Which image best illustrates the electric field lines between the inside of an axon andthe surrounding extracellular solution?
- arrows pointing right into the
extracellular fluidB. arrows pointing left into the axon interiorC. arrows pointing down the axon interiorD. arrows pointing up the axon interior correct answersAnswer is B.Electric field lines exit from positive and enter negative charges - technically it is morenegative inside the axon and positive in the extracellular One function of the myeline sheath
is to:
- insulate the axon from the
surroundingsB. decrease the radius of the axonC. produce Schwann cellsD. increase the capacitance of the axon correct answersAnswer is A.insulate the axonfrom the surroundings Additionally, myelin sheath INCREASES RADIUS + is formed BY THE
SCHWANNCELLS + DECREASES CAPACITANCE
Channel X transmits only the smallest substances dissolved in the extracellular fluidthrough the axon membrane. Which substance does Channel X transmit?A.proteinsB. sodium ionsC. potassium ionsD. chloride ions correct answersAnswer is B.sodium ions sodium cations are small by virtue of their positive charge and low atomic number (justlook at amu on periodic table) *What is the closest distance the electrodes used in an NCV test can be placed on anerve in order to measure the voltage change as a response to the stimulus?
A. 0.01
mB. 0.1 mC. 1.0
mD. 10 m correct answersAnswer is: B.
0.1 m Figure 2 says the shortest duration that can be detected/resolved is 1 msec. Thedistance travelled by this is 1 msec x (1 sec/1000 msec) x (100 m/sec) = 0.1 m
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