MCAT Practice Exam 3: Biological and
Biochemical Foundations of Living Systems
with Answers
Question 1
Assuming that protein synthesis was under way when the radioactive amino acids
were added, which of the following describes how the radioactivity was distributed in
one of the first molecules of Protein X that was completely translated?
A. Radioactive amino acids were randomly located throughout the molecule
B. Radioactive amino acids were located at only one end of the molecule
C. Radioactive amino acids were located at both ends, but not in the middle, of the
molecule
D. Radioactive amino acids were located in the middle, but not at either end of the
molecule
Correct Answer
Correct answer: B
Infer that the N-part of the amino acid and most of the middle is already
synthesized
Question 2
Large amounts of protein are found in the urine of a patient. Based on this
information, which portion of the nephron is most likely malfunctioning?
A. Collecting duct
B. Distal tubule
C. Glomerulus
D. Loop of Henle
Correct Answer
Correct answer: C
The small capillaries of the glomerulus prevent large particles from entering the
filtrate
Page 1 of 6
, Question 3
Primary vs secondary active transport
Correct Answer
Primary - transport directly coupled with ATP
Secondary- ATP first used to create a gradient and the potential energy is used to
drive something across membrane
Question 4
SSRIs most likely relieve depression by increasing the:
A. amount of serotonin that is absorbed by the postsynaptic neuron
B. release of serotonin by the presynaptic neuron
C. rate of serotonin synthesis in the presynaptic neuron
D. amount of time that serotonin is present in the synaptic space
Correct Answer
Correct answer: D
SSRIs function by decreasing presynaptic neuron uptake of serotonin, thereby
increasing time in the synaptic space
Question 5
Based on the information in the passage, what is the most likely mechanism of
inheritance for HPRCC?
A. Autosomal dominant
B. Autosomal recessive
C. X-linked recessive
D. Y-linked
Correct Answer
Correct answer: A
Not X-linked recessive because two affected individuals have two affected offspring
Page 2 of 6
Biochemical Foundations of Living Systems
with Answers
Question 1
Assuming that protein synthesis was under way when the radioactive amino acids
were added, which of the following describes how the radioactivity was distributed in
one of the first molecules of Protein X that was completely translated?
A. Radioactive amino acids were randomly located throughout the molecule
B. Radioactive amino acids were located at only one end of the molecule
C. Radioactive amino acids were located at both ends, but not in the middle, of the
molecule
D. Radioactive amino acids were located in the middle, but not at either end of the
molecule
Correct Answer
Correct answer: B
Infer that the N-part of the amino acid and most of the middle is already
synthesized
Question 2
Large amounts of protein are found in the urine of a patient. Based on this
information, which portion of the nephron is most likely malfunctioning?
A. Collecting duct
B. Distal tubule
C. Glomerulus
D. Loop of Henle
Correct Answer
Correct answer: C
The small capillaries of the glomerulus prevent large particles from entering the
filtrate
Page 1 of 6
, Question 3
Primary vs secondary active transport
Correct Answer
Primary - transport directly coupled with ATP
Secondary- ATP first used to create a gradient and the potential energy is used to
drive something across membrane
Question 4
SSRIs most likely relieve depression by increasing the:
A. amount of serotonin that is absorbed by the postsynaptic neuron
B. release of serotonin by the presynaptic neuron
C. rate of serotonin synthesis in the presynaptic neuron
D. amount of time that serotonin is present in the synaptic space
Correct Answer
Correct answer: D
SSRIs function by decreasing presynaptic neuron uptake of serotonin, thereby
increasing time in the synaptic space
Question 5
Based on the information in the passage, what is the most likely mechanism of
inheritance for HPRCC?
A. Autosomal dominant
B. Autosomal recessive
C. X-linked recessive
D. Y-linked
Correct Answer
Correct answer: A
Not X-linked recessive because two affected individuals have two affected offspring
Page 2 of 6
