USABO OPEN EXAM –ACTUAL EXAM-LATEST UPDATE 2025-COMPLETE
QUESTIONS WITH CORRECT DETAILED AND VERIFIED ANSWERS | RATED
100% CORRECT!! GUARANTEED PASS!! ALREADY GRADED A+
What enzyme does HIV use to convert RNA to DNA?
[ ] A. DNA gyrase
[ ] B. RNA polymerase
[ ] C. Reverse transcriptase
[ ] D. DNA helicase - (answers)C
Which of the following is TRUE of prokaryotes?
I. Simultaneous transcription and translation
II. Presence of intron sequences
III. Circular DNA
[ ] A. I and II only
[ ] B. I and III only
[ ] C. II and III only
[ ] D. I, II, and III - (answers)B
The promoter region of a prokaryotic gene is located ______ to the gene and is the binding site
for ______.
[ ] A. 3'...DNA polymerase
[ ] B. 3'...RNA polymerase
[ ] C. 5'...DNA polymerase
[ ] D. 5'...RNA polymerase - (answers)D
. 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?
,[ ] A. Lysine
[ ] B. Serine
[ ] C. Tryptophan
[ ] D. Arginine - (answers)C Tryptophan
(it is non polar and does not have a charge)
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 equilibrium, what is
the proportion of carrier individuals in this population?
[ ] A. 12.5%
[ ] B. 25%
[ ] C. 50%
[ ] D. 100% - (answers)C 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?
[ ] A. Oligodendocyte
[ ] B. Astrocyte
[ ] C. Schwann cell
[ ] D. Microglial cell - (answers)Schwann cell
Rods and cones are associated with _____ and _____ vision, respectively.
[ ] A. Light/dark...color
[ ] B. Color...light/dark
[ ] C. Near...far
[ ] D. Far...near - (answers)A
In many types of cancer, the function of the p53 gene is lost. Wild-type p53 is MOST likely to be
a
[ ] A. proto-oncogene
,[ ] B. tumor suppressor
[ ] C. positive regulator of cell cycle progression
[ ] D. gene required for DNA replication - (answers)B
What glycolytic product is shuttled to the mitochondria in aerobic respiration?
[ ] A. Acetyl-CoA
[ ] B. Fumarate
[ ] C. Succinyl-CoA
[ ] D. Pyruvate - (answers)D
Telomerase is responsible for _____ the size of telomeres, and its function is often ____ in
carcinogenesis.
[ ] A. maintaining ... decreased
[ ] B. maintaining ... increased
[ ] C. decreasing ... decreased
[ ] D. decreasing ... increased - (answers)B
Which of the following is NOT a mode of natural selection?
[ ] A. stabilizing selection
[ ] B. sexual selection
[ ] C. directional selection
[ ] D. diversifying selection - (answers)B
Protostomes have _____ and _____ types of cleavage.
[ ] A. spiral ... determinate
[ ] B. spiral ... indeterminate
[ ] C. radial ... determinate
[ ] D. radial ... indeterminate - (answers)A Pg 661
, Which of the following is NOT a characteristic of all chordates?
[ ] A. notochord
[ ] B. vertebrae
[ ] C. pharyngeal slits
[ ] D. postanal tail - (answers)B
Unlike most polypeptide hormones, steroid hormones are unique in that they
[ ] A. Activate gene transcription
[ ] B. Diffuse across cell membranes
[ ] C. Can bind proteins
[ ] D. Can be used as therapeutic drugs - (answers)B
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)
[ ] A. coenzyme
[ ] B. cofactor
[ ] C. allosteric activator
[ ] D. allosteric inhibitor - (answers)B
The order of normal blood flow through the human heart is
[ ] A. right ventricle, right atrium, lungs, left ventricle, left atrium, body
[ ] B. right ventricle, right atrium, body, left ventricle, left atrium, lungs
[ ] C. right atrium, right ventricle, lungs, left atrium, left ventricle, body
[ ] D. right atrium, right ventricle, body, left atrium, left ventricle, lungs - (answers)C
Allopatric speciation refers to species formed after which type of separation:
[ ] A. niche
[ ] B. temporal
QUESTIONS WITH CORRECT DETAILED AND VERIFIED ANSWERS | RATED
100% CORRECT!! GUARANTEED PASS!! ALREADY GRADED A+
What enzyme does HIV use to convert RNA to DNA?
[ ] A. DNA gyrase
[ ] B. RNA polymerase
[ ] C. Reverse transcriptase
[ ] D. DNA helicase - (answers)C
Which of the following is TRUE of prokaryotes?
I. Simultaneous transcription and translation
II. Presence of intron sequences
III. Circular DNA
[ ] A. I and II only
[ ] B. I and III only
[ ] C. II and III only
[ ] D. I, II, and III - (answers)B
The promoter region of a prokaryotic gene is located ______ to the gene and is the binding site
for ______.
[ ] A. 3'...DNA polymerase
[ ] B. 3'...RNA polymerase
[ ] C. 5'...DNA polymerase
[ ] D. 5'...RNA polymerase - (answers)D
. 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?
,[ ] A. Lysine
[ ] B. Serine
[ ] C. Tryptophan
[ ] D. Arginine - (answers)C Tryptophan
(it is non polar and does not have a charge)
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 equilibrium, what is
the proportion of carrier individuals in this population?
[ ] A. 12.5%
[ ] B. 25%
[ ] C. 50%
[ ] D. 100% - (answers)C 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?
[ ] A. Oligodendocyte
[ ] B. Astrocyte
[ ] C. Schwann cell
[ ] D. Microglial cell - (answers)Schwann cell
Rods and cones are associated with _____ and _____ vision, respectively.
[ ] A. Light/dark...color
[ ] B. Color...light/dark
[ ] C. Near...far
[ ] D. Far...near - (answers)A
In many types of cancer, the function of the p53 gene is lost. Wild-type p53 is MOST likely to be
a
[ ] A. proto-oncogene
,[ ] B. tumor suppressor
[ ] C. positive regulator of cell cycle progression
[ ] D. gene required for DNA replication - (answers)B
What glycolytic product is shuttled to the mitochondria in aerobic respiration?
[ ] A. Acetyl-CoA
[ ] B. Fumarate
[ ] C. Succinyl-CoA
[ ] D. Pyruvate - (answers)D
Telomerase is responsible for _____ the size of telomeres, and its function is often ____ in
carcinogenesis.
[ ] A. maintaining ... decreased
[ ] B. maintaining ... increased
[ ] C. decreasing ... decreased
[ ] D. decreasing ... increased - (answers)B
Which of the following is NOT a mode of natural selection?
[ ] A. stabilizing selection
[ ] B. sexual selection
[ ] C. directional selection
[ ] D. diversifying selection - (answers)B
Protostomes have _____ and _____ types of cleavage.
[ ] A. spiral ... determinate
[ ] B. spiral ... indeterminate
[ ] C. radial ... determinate
[ ] D. radial ... indeterminate - (answers)A Pg 661
, Which of the following is NOT a characteristic of all chordates?
[ ] A. notochord
[ ] B. vertebrae
[ ] C. pharyngeal slits
[ ] D. postanal tail - (answers)B
Unlike most polypeptide hormones, steroid hormones are unique in that they
[ ] A. Activate gene transcription
[ ] B. Diffuse across cell membranes
[ ] C. Can bind proteins
[ ] D. Can be used as therapeutic drugs - (answers)B
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)
[ ] A. coenzyme
[ ] B. cofactor
[ ] C. allosteric activator
[ ] D. allosteric inhibitor - (answers)B
The order of normal blood flow through the human heart is
[ ] A. right ventricle, right atrium, lungs, left ventricle, left atrium, body
[ ] B. right ventricle, right atrium, body, left ventricle, left atrium, lungs
[ ] C. right atrium, right ventricle, lungs, left atrium, left ventricle, body
[ ] D. right atrium, right ventricle, body, left atrium, left ventricle, lungs - (answers)C
Allopatric speciation refers to species formed after which type of separation:
[ ] A. niche
[ ] B. temporal
