USABO Practice Questions with Complete
Solutions (Latest 2025)
What enzyme does HIV use to convert RNA to DNA? - Correct
Answers ✅Reverse Transcriptase
The promoter region of a prokaryotic gene is located ______ to
the gene and is the binding site for ______. - Correct
Answers ✅5'...RNA polymerase
Which of the following is TRUE of prokaryotes?
I. Simultaneous transcription and translation
II. Presence of intron sequences
III. Circular DNA - Correct Answers ✅I and III only
Integral transmembrane proteins are proteins imbedded in
the cell membrane. Which of the following amino acids would
you MOST expect to find in the transmembrane region of
such proteins? - Correct Answers ✅Tryptophan
When the base composition of DNA from bacterium
Mycobacterium tuberculosis was determined, 18% of the
bases were found to be adenine. What is the G + C content in
M. tuberculosis? - Correct Answers ✅64%
The frequency of individuals affected with an autosomally
recessive inherited disorder is 1 in 4. Assuming that the
population affected by this disease is in Hardy-Weinberg
,USABO Practice Questions with Complete
Solutions (Latest 2025)
equilibrium, what is the proportion of carrier individuals in
this population? - Correct Answers ✅50%
The velocity of action potential conduction across a nerve
axon is increased by the presence of the myelin sheath. In
the peripheral nervous system, what cell myelinates the
axon? - Correct Answers ✅schwann cell
The cell bodies of afferent (sensory) nerves involved in
somatic reflexes are located in the - Correct Answers
✅Dorsal root ganglion
Rods and cones are associated with _____ and _____ vision,
respectively. - Correct Answers ✅Light/dark...color
Populations that are likely to be living at a density near the
limit of their resources, are characterized as - Correct
Answers ✅K-selected
In many types of cancer, the function of the p53 gene is lost.
Wild-type p53 is MOST likely to be a - Correct Answers
✅tumor suppressor
What glycolytic product is shuttled to the mitochondria in
aerobic respiration? - Correct Answers ✅Pyruvate
,USABO Practice Questions with Complete
Solutions (Latest 2025)
During human development, which process leads to the
formation of three germ layers? - Correct Answers
✅gastrulation
Telomerase is responsible for _____ the size of telomeres, and
its function is often ____ in carcinogenesis. - Correct
Answers ✅maintaining ... increased
Which of the following is NOT a mode of natural selection? -
Correct Answers ✅sexual selection
Protostomes have _____ and _____ types of cleavage. -
Correct Answers ✅spiral ... determinate
Which of the following is NOT a characteristic of all
chordates? - Correct Answers ✅vertebrae
In cardiac muscle, calcium ions can move freely between
adjacent cells through which of the following? - Correct
Answers ✅gap junctions
Unlike most polypeptide hormones, steroid hormones are
unique in that they - Correct Answers ✅Diffuse across cell
membranes
, USABO Practice Questions with Complete
Solutions (Latest 2025)
In superoxide dismutase 1, an enzyme implicated in
amyotrophic lateral sclerosis (Lou Gehrig's disease), a copper
ion is bound to the active site and is important for enzyme
activity. In this enzyme, copper most likely functions as a(n) -
Correct Answers ✅cofactor
The order of normal blood flow through the human heart is -
Correct Answers ✅right atrium, right ventricle, lungs, left
atrium, left ventricle, body
Allopatric speciation refers to species formed after which type
of separation: - Correct Answers ✅geographic
Which two functional groups are always found in amino
acids? - Correct Answers ✅Carboxyl and amine
Movement of ions across the membrane from higher to lower
concentrations through a channel protein is an example of -
Correct Answers ✅Facilitated diffusion
Which group of plants has vascular tissue but does not
produce seeds?
I. Mosses
II. Ferns
III. Gymnosperms - Correct Answers ✅II
Solutions (Latest 2025)
What enzyme does HIV use to convert RNA to DNA? - Correct
Answers ✅Reverse Transcriptase
The promoter region of a prokaryotic gene is located ______ to
the gene and is the binding site for ______. - Correct
Answers ✅5'...RNA polymerase
Which of the following is TRUE of prokaryotes?
I. Simultaneous transcription and translation
II. Presence of intron sequences
III. Circular DNA - Correct Answers ✅I and III only
Integral transmembrane proteins are proteins imbedded in
the cell membrane. Which of the following amino acids would
you MOST expect to find in the transmembrane region of
such proteins? - Correct Answers ✅Tryptophan
When the base composition of DNA from bacterium
Mycobacterium tuberculosis was determined, 18% of the
bases were found to be adenine. What is the G + C content in
M. tuberculosis? - Correct Answers ✅64%
The frequency of individuals affected with an autosomally
recessive inherited disorder is 1 in 4. Assuming that the
population affected by this disease is in Hardy-Weinberg
,USABO Practice Questions with Complete
Solutions (Latest 2025)
equilibrium, what is the proportion of carrier individuals in
this population? - Correct Answers ✅50%
The velocity of action potential conduction across a nerve
axon is increased by the presence of the myelin sheath. In
the peripheral nervous system, what cell myelinates the
axon? - Correct Answers ✅schwann cell
The cell bodies of afferent (sensory) nerves involved in
somatic reflexes are located in the - Correct Answers
✅Dorsal root ganglion
Rods and cones are associated with _____ and _____ vision,
respectively. - Correct Answers ✅Light/dark...color
Populations that are likely to be living at a density near the
limit of their resources, are characterized as - Correct
Answers ✅K-selected
In many types of cancer, the function of the p53 gene is lost.
Wild-type p53 is MOST likely to be a - Correct Answers
✅tumor suppressor
What glycolytic product is shuttled to the mitochondria in
aerobic respiration? - Correct Answers ✅Pyruvate
,USABO Practice Questions with Complete
Solutions (Latest 2025)
During human development, which process leads to the
formation of three germ layers? - Correct Answers
✅gastrulation
Telomerase is responsible for _____ the size of telomeres, and
its function is often ____ in carcinogenesis. - Correct
Answers ✅maintaining ... increased
Which of the following is NOT a mode of natural selection? -
Correct Answers ✅sexual selection
Protostomes have _____ and _____ types of cleavage. -
Correct Answers ✅spiral ... determinate
Which of the following is NOT a characteristic of all
chordates? - Correct Answers ✅vertebrae
In cardiac muscle, calcium ions can move freely between
adjacent cells through which of the following? - Correct
Answers ✅gap junctions
Unlike most polypeptide hormones, steroid hormones are
unique in that they - Correct Answers ✅Diffuse across cell
membranes
, USABO Practice Questions with Complete
Solutions (Latest 2025)
In superoxide dismutase 1, an enzyme implicated in
amyotrophic lateral sclerosis (Lou Gehrig's disease), a copper
ion is bound to the active site and is important for enzyme
activity. In this enzyme, copper most likely functions as a(n) -
Correct Answers ✅cofactor
The order of normal blood flow through the human heart is -
Correct Answers ✅right atrium, right ventricle, lungs, left
atrium, left ventricle, body
Allopatric speciation refers to species formed after which type
of separation: - Correct Answers ✅geographic
Which two functional groups are always found in amino
acids? - Correct Answers ✅Carboxyl and amine
Movement of ions across the membrane from higher to lower
concentrations through a channel protein is an example of -
Correct Answers ✅Facilitated diffusion
Which group of plants has vascular tissue but does not
produce seeds?
I. Mosses
II. Ferns
III. Gymnosperms - Correct Answers ✅II
