AAMC Biological and Biochemical
Foundations of Living Systems Exam
Questions and Answers
Question 1
Organic acids, denoted by HA, are only minimally deprotonated when added to pure
water.
HA(aq) BB-8-1-MCAT Double Arrow.gif H+(aq) + A-(aq)
When dissolved in blood, however, HA fully dissociate. What factor can be used to
explain this discrepancy?
A.In blood, the concentration of H+(aq) is maintained at low levels by other equilibria.
B.In blood, the reaction is coupled to ATP hydrolysis to make it more favorable.
C.In blood, the ionic strength of the solvent medium is much higher than pure water.
D.In blood, enzymes are used to catalyze the dissociation reaction.
Correct Answer
the answer to this question is A because the chemical equation shows that H+ is a
product of the reaction. Due to Le Châtelier's Principle, the equilibrium will favor
products when the concentration of products is kept low.
Page 1 of 59
,Question 2
The information in the passage suggests that which symptom or characteristic of
malaria is PfEMP1-mediated?
PfEMP1 enhances P. falciparum survival by binding infected erythrocytes to
endothelium. Different PfEMP1 subsets bind different endothelial proteins; for
example, binding of infected erythrocytes to ICAM1 protein in brain venules causes
cerebral malaria.
A.Blood vessel blockage
B.Low red blood cell count
C.Recurring fever and chills
D.Sickle cell hemoglobin-mediated malaria resistance
Correct Answer
the answer to this question is A because PfEMP1 binds the parasite-infected
erythrocytes to endothelium, and red blood cells stuck to blood vessel walls will
likely cause blood vessel blockage. Even without more details about the parasite life
cycle, this is the most obvious answer. Symptoms associated with parasite-mediated
rupture of erythrocytes (B, C) or the increased clearance of infected erythrocytes in
people with sickle cell trait (D) are not obviously so directly caused by PfEMP1.
Question 3
To be an effective therapy, an antisense gene that is incorporated into a genome that
contains the target gene must be:
A. on the same chromosome as the target gene but not necessarily be physically
adjacent.
B. on the same chromosome as the target gene and must be physically adjacent.
C. regulated in a similar manner as the target gene.
D. coded on the same strand of DNA as the target gene.
Correct Answer
To provide effective therapy, this antisense gene would need to be regulated in a
manner similar to the manner in which the target gene is regulated so that the
antisense RNA is produced at the same time that the sense mRNA is produced. This
would ensure that the antisense RNA is available to bind with the sense mRNA,
thereby preventing its subsequent translation. As a result, C is correct.
Page 2 of 59
,Question 4
Which component of the electron transport chain is defective in cells from an SDH-
linked paraganglioma tumor?
A.Complex I
B.Complex II
C.Complex III
D.Complex IV
Correct Answer
The answer to this question is B because the passage states that the paraganglioma
tumor is associated with loss of function of succinate dehydrogenase, which is also
known as Complex II, in the electron transport chain.
Question 5
Define deliterious
Correct Answer
causing harm or damage
Question 6
Two gel electrophoresis analyses are performed on a sample of purified protein with
unknown structure: SDS-PAGE (1 band appears) and SDS-PAGE under reducing
conditions (2 bands appear). Which prediction about the protein is directly supported
by these results? The protein:
is posttranslationally glycosylated.
contains a high proportion of charged residues.
contains no disulfide bonds.
is composed of multiple subunits.
Correct Answer
The answer to this question is D because a reducing agent is used during SDS-PAGE
to cleave disulfide bonds. The appearance of 1 band on SDS-PAGE without the
reducing agent and 2 bands on SDS-PAGE with a reducing agent, suggests that at
least one disulfide bond is present in the protein and that the disulfide bond(s)
hold(s) two separate subunits of different masses together.
Page 3 of 59
, Question 7
The scientist wanted to use antibody B clinically (to treat humans), but this proposal
was rejected. Which of the following is the most logical reason for the rejection?
A.Because the antibody was generated in the mouse, it can never be used in humans.
B.Because the antibody was generated in the mouse, repeated usage in the same
patient would elicit the production of human anti-mouse antibodies.
C.Because the antibody was generated in the mouse, it will not recognize human
antigens.
D.Because the antibody was generated in the mouse, it can only be used in vitro.
Correct Answer
The answer to this question is B because the human immune system will recognize
the mouse antibody as a foreign substance (antigen) and generate an immune
response towards it, which may include a mild to severe allergic response. The
immune response will generate antibodies against the mouse antibody, limiting its
usefulness as a treatment.
Question 8
Upon binding, IN catalyzes cleavage of a GT dinucleotide from each 3PRIME vDNA
terminus.
What bond is cleaved by IN during the first reaction of integration?
P-C
P-P
P-H
P-O
Correct Answer
the answer to this question is D because in the first reaction of integration,
integrase cleaves a dinucleotide from the 3BB-8-1-prime.gif end of a strand of viral
DNA. This involves the cleavage of a P-O bond.
Page 4 of 59
Foundations of Living Systems Exam
Questions and Answers
Question 1
Organic acids, denoted by HA, are only minimally deprotonated when added to pure
water.
HA(aq) BB-8-1-MCAT Double Arrow.gif H+(aq) + A-(aq)
When dissolved in blood, however, HA fully dissociate. What factor can be used to
explain this discrepancy?
A.In blood, the concentration of H+(aq) is maintained at low levels by other equilibria.
B.In blood, the reaction is coupled to ATP hydrolysis to make it more favorable.
C.In blood, the ionic strength of the solvent medium is much higher than pure water.
D.In blood, enzymes are used to catalyze the dissociation reaction.
Correct Answer
the answer to this question is A because the chemical equation shows that H+ is a
product of the reaction. Due to Le Châtelier's Principle, the equilibrium will favor
products when the concentration of products is kept low.
Page 1 of 59
,Question 2
The information in the passage suggests that which symptom or characteristic of
malaria is PfEMP1-mediated?
PfEMP1 enhances P. falciparum survival by binding infected erythrocytes to
endothelium. Different PfEMP1 subsets bind different endothelial proteins; for
example, binding of infected erythrocytes to ICAM1 protein in brain venules causes
cerebral malaria.
A.Blood vessel blockage
B.Low red blood cell count
C.Recurring fever and chills
D.Sickle cell hemoglobin-mediated malaria resistance
Correct Answer
the answer to this question is A because PfEMP1 binds the parasite-infected
erythrocytes to endothelium, and red blood cells stuck to blood vessel walls will
likely cause blood vessel blockage. Even without more details about the parasite life
cycle, this is the most obvious answer. Symptoms associated with parasite-mediated
rupture of erythrocytes (B, C) or the increased clearance of infected erythrocytes in
people with sickle cell trait (D) are not obviously so directly caused by PfEMP1.
Question 3
To be an effective therapy, an antisense gene that is incorporated into a genome that
contains the target gene must be:
A. on the same chromosome as the target gene but not necessarily be physically
adjacent.
B. on the same chromosome as the target gene and must be physically adjacent.
C. regulated in a similar manner as the target gene.
D. coded on the same strand of DNA as the target gene.
Correct Answer
To provide effective therapy, this antisense gene would need to be regulated in a
manner similar to the manner in which the target gene is regulated so that the
antisense RNA is produced at the same time that the sense mRNA is produced. This
would ensure that the antisense RNA is available to bind with the sense mRNA,
thereby preventing its subsequent translation. As a result, C is correct.
Page 2 of 59
,Question 4
Which component of the electron transport chain is defective in cells from an SDH-
linked paraganglioma tumor?
A.Complex I
B.Complex II
C.Complex III
D.Complex IV
Correct Answer
The answer to this question is B because the passage states that the paraganglioma
tumor is associated with loss of function of succinate dehydrogenase, which is also
known as Complex II, in the electron transport chain.
Question 5
Define deliterious
Correct Answer
causing harm or damage
Question 6
Two gel electrophoresis analyses are performed on a sample of purified protein with
unknown structure: SDS-PAGE (1 band appears) and SDS-PAGE under reducing
conditions (2 bands appear). Which prediction about the protein is directly supported
by these results? The protein:
is posttranslationally glycosylated.
contains a high proportion of charged residues.
contains no disulfide bonds.
is composed of multiple subunits.
Correct Answer
The answer to this question is D because a reducing agent is used during SDS-PAGE
to cleave disulfide bonds. The appearance of 1 band on SDS-PAGE without the
reducing agent and 2 bands on SDS-PAGE with a reducing agent, suggests that at
least one disulfide bond is present in the protein and that the disulfide bond(s)
hold(s) two separate subunits of different masses together.
Page 3 of 59
, Question 7
The scientist wanted to use antibody B clinically (to treat humans), but this proposal
was rejected. Which of the following is the most logical reason for the rejection?
A.Because the antibody was generated in the mouse, it can never be used in humans.
B.Because the antibody was generated in the mouse, repeated usage in the same
patient would elicit the production of human anti-mouse antibodies.
C.Because the antibody was generated in the mouse, it will not recognize human
antigens.
D.Because the antibody was generated in the mouse, it can only be used in vitro.
Correct Answer
The answer to this question is B because the human immune system will recognize
the mouse antibody as a foreign substance (antigen) and generate an immune
response towards it, which may include a mild to severe allergic response. The
immune response will generate antibodies against the mouse antibody, limiting its
usefulness as a treatment.
Question 8
Upon binding, IN catalyzes cleavage of a GT dinucleotide from each 3PRIME vDNA
terminus.
What bond is cleaved by IN during the first reaction of integration?
P-C
P-P
P-H
P-O
Correct Answer
the answer to this question is D because in the first reaction of integration,
integrase cleaves a dinucleotide from the 3BB-8-1-prime.gif end of a strand of viral
DNA. This involves the cleavage of a P-O bond.
Page 4 of 59
