2. What assumption is being made if scientists conclude aspartic acid was formed by the prebiological synthesis in the passage?
A. Aspartic acid is unstable at temperatures below 150C
B. All of the malic acid underwent the dehydration reaction to form fumaric/maleic acid
C. Compound A and cyan...
AAMC FL 1 C/P || All Correct.
2. What assumption is being made if scientists conclude aspartic acid was formed by the
prebiological synthesis in the passage?
A. Aspartic acid is unstable at temperatures below 150C
B. All of the malic acid underwent the dehydration reaction to form fumaric/maleic acid
C. Compound A and cyanide were available on primitive Earth
D. the reaction between ammonia and fumaric acid was catalyzed by the presence of water.
correct answers C.
In order for the experimental reaction sequence to be relevant to the primordial formation of
aspartic acid, the starting materials used (Compound A and cyanide) are assumed to have been
available.
4. Which of the following statements does NOT correctly describe the dehydration of malic acid
to fumaric acid and maleic acid?
A. The reaction occurs most readily with tertiary alcohols.
B. The reaction involves the loss of a water molecule.
C. The reaction has a carbocation intermediate.
D. The reaction is stereospecific. correct answers D.
the fact that both fumaric and maleic acid are produced means that the dehydration of malic acid
is NOT stereospecific.
5. What type of functional group is formed when aspartic acid reacts with another amino acid to
form a peptide bond?
A. An amine group
B. An aldehyde group
C. An amide group
D. A carboxyl group correct answers C.
The functional group that forms during peptide bond formation is an amide group.
6. If 2-pentanol replaces 1-pentanol in the reaction shown in Figure 3, the rate of substitution is
less because:
A. the C-O bond in 2-pentanol is stronger than the C-O bond in 1-pentanol.
B. there is a competing elimination reaction that slows the rate of substitution.
C. there is more steric hindrance at the oxygen atom in 2-pentanol than in 1-pentanol, making
protonation less likely.
D. there is more steric hindrance at the 2-position of 2-pentanol than at the 1-position of 1-
pentanol. correct answers D.
, The rate of substitution of protonated alcohols is subject to steric hindrance. This inhibits the
ability of nucleophiles to collide with the reacting electrophilic center and slows down the rate of
reaction.
10. In determining which reactant loses the -OH group, which of the following isotopic
substitutions would be most useful?
A. Replace the acidic H of acetic acid with D.
B. Replace the alcoholic H of ethanol with D.
C. Replace the carbonyl oxygen of acetic acid with O-18.
D. Replace the hydroxyl oxygen of ethanol with O-18. correct answers D.
This experiment involves labeling a group which does not exchange with other groups present
prior to reaction and will therefore give information about the true identity of the groups, which
are exchanged during the reaction.
We want acetic acid to keep their Oxygen when forming the ester so we ass O-18 to ethanol to
be sure no exchange happens prior to reacting.
14. When the current in the micro-robot's circuit increases and the resistance of the circuit
remains constant, the voltage of the circuit:
A. decreases.
B. increases.
C. is constant.
D. is zero. correct answers B.
According to Ohm's law, current is equal to voltage divided by resistance. If current increases
and resistance is constant, then voltage increases as well.
18. What is the relationship between Pp, PMPA, and Pd?
A. Pp = PMPA + 3Pd
B. Pp = 3PMPA + Pd
C. Pp = 3PMPA − 3Pd
D. Pp = PMPA − 3Pd correct answers C.
according to Equation 1, PPMA = Pd + (Ps - Pd)/3 = Pd +Pp/3; thus Pp = 3PMPA - 3Pd.
20. What fraction of a 15O sample decays in 10 min?
A. 1/8
B. 9/16
C. 3/4
D. 31/32 correct answers D.
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