AAMC 3 Bio/bio Questions With Complete Solutions
A certain drug blocks the activity of enzyme A by
reversibly binding the enzyme's active site. Given
this, the drug most likely inhibits enzyme A's
activity by: Correct Answers competitive inhibition
- in competitive inhibition, the inhibitor reversibly
binds the enzyme's active site.
- easy
A drug that inhibits the activity of which of the
following enzymes would be most likely to relieve
depression in some people, assuming the chemical
reactions in Figure 1 are irreversible? Correct
Answers Monamine oxidase A
- based on the data in Figure 1, monoamine
oxidase A is involved in oxidation and degradation
of serotonin. Therefore, a drug that inhibits the
activity of monoamine oxidase A would be most
likely to relieve depression.
- easy
According to the passage, relative to slow-twitch
fibers, fast-twitch fibers are likely to exhibit which
property? Correct Answers - greater Ca2+
pumping capacity.
slow-twitch fibers are adapted for aerobic exercise
which suggests they are likely, relative to fast-
twitch fibers, to have increased capillary density,
larger numbers of mitochondria, and higher levels
,of oxygen-binding proteins. The names of the
fibers themselves give insight into their relative
rates of contraction. Thus, it is unlikely that slow-
twitch fibers will have greater Ca2+-pumping
capacity, than fast-twitch fibers.
Allosteric inhibition of an enzyme involves which of
the following events? Correct Answers Binding of
an inhibitor to a site other than the substrate
binding site
- easy
Assume that a certain species with sex
chromosomes R and S exists such that RR
individuals develop as males and RS individuals
develop as females. Which of the following
mechanisms would most likely compensate for the
potential imbalance of sex-chromosome gene
products between males and females of this
species? Correct Answers - inactivation of one R
chromosome in males
because males of the species have two copies of
the R chromosome, whereas females have one R
chromosome and one S chromosome. Therefore, in
order to compensate for a potential imbalance of
sex chromosomes between females and males,
one R chromosome should be inactivated in males.
Assume that the rate of protein synthesis is greater
when the culture is incubated at 45°C than at
, 37°C. Which of the following graphs shows how
temperature will influence the results in Figure 1?
Correct Answers because in this experiment, the
rate of protein synthesis is directly proportional to
the level of radioactivity, and option B is the only
option that exhibits a faster increase in
radioactivity at 45 °C than at 37 °C
- read graph
Assuming that protein synthesis was under way
when the radioactive amino acids were added,
which of the following best describes how the
radioactivity was distributed in one of the first
molecules of Protein X that was completely
translated? Correct Answers radioactive amino
acids were located only at one end of the molecule
- the stem assumes that protein synthesis was
under way when the radioactive amino acids were
added, inferring that the N-terminal end and
probably the middle part of the protein were
already synthesized before the addition of the
radioactive amino acids.
Assuming the duration of contraction is the same,
which point on the power curve corresponds to the
LEAST amount of work being done by the muscle?
Correct Answers point A
- work is the product of force applied over a
distance an object is moved (or in this case, a
muscle contracts).
A certain drug blocks the activity of enzyme A by
reversibly binding the enzyme's active site. Given
this, the drug most likely inhibits enzyme A's
activity by: Correct Answers competitive inhibition
- in competitive inhibition, the inhibitor reversibly
binds the enzyme's active site.
- easy
A drug that inhibits the activity of which of the
following enzymes would be most likely to relieve
depression in some people, assuming the chemical
reactions in Figure 1 are irreversible? Correct
Answers Monamine oxidase A
- based on the data in Figure 1, monoamine
oxidase A is involved in oxidation and degradation
of serotonin. Therefore, a drug that inhibits the
activity of monoamine oxidase A would be most
likely to relieve depression.
- easy
According to the passage, relative to slow-twitch
fibers, fast-twitch fibers are likely to exhibit which
property? Correct Answers - greater Ca2+
pumping capacity.
slow-twitch fibers are adapted for aerobic exercise
which suggests they are likely, relative to fast-
twitch fibers, to have increased capillary density,
larger numbers of mitochondria, and higher levels
,of oxygen-binding proteins. The names of the
fibers themselves give insight into their relative
rates of contraction. Thus, it is unlikely that slow-
twitch fibers will have greater Ca2+-pumping
capacity, than fast-twitch fibers.
Allosteric inhibition of an enzyme involves which of
the following events? Correct Answers Binding of
an inhibitor to a site other than the substrate
binding site
- easy
Assume that a certain species with sex
chromosomes R and S exists such that RR
individuals develop as males and RS individuals
develop as females. Which of the following
mechanisms would most likely compensate for the
potential imbalance of sex-chromosome gene
products between males and females of this
species? Correct Answers - inactivation of one R
chromosome in males
because males of the species have two copies of
the R chromosome, whereas females have one R
chromosome and one S chromosome. Therefore, in
order to compensate for a potential imbalance of
sex chromosomes between females and males,
one R chromosome should be inactivated in males.
Assume that the rate of protein synthesis is greater
when the culture is incubated at 45°C than at
, 37°C. Which of the following graphs shows how
temperature will influence the results in Figure 1?
Correct Answers because in this experiment, the
rate of protein synthesis is directly proportional to
the level of radioactivity, and option B is the only
option that exhibits a faster increase in
radioactivity at 45 °C than at 37 °C
- read graph
Assuming that protein synthesis was under way
when the radioactive amino acids were added,
which of the following best describes how the
radioactivity was distributed in one of the first
molecules of Protein X that was completely
translated? Correct Answers radioactive amino
acids were located only at one end of the molecule
- the stem assumes that protein synthesis was
under way when the radioactive amino acids were
added, inferring that the N-terminal end and
probably the middle part of the protein were
already synthesized before the addition of the
radioactive amino acids.
Assuming the duration of contraction is the same,
which point on the power curve corresponds to the
LEAST amount of work being done by the muscle?
Correct Answers point A
- work is the product of force applied over a
distance an object is moved (or in this case, a
muscle contracts).
