USABO Practice 2025/2026 Exam
Questions and Answers 100%
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What enzyme does HIV use to convert RNA to DNA? - 🧠 ANSWER
✔✔Reverse Transcriptase
The promoter region of a prokaryotic gene is located ______ to the gene
and is the binding site for ______. - 🧠 ANSWER ✔✔5'...RNA polymerase
Which of the following is TRUE of prokaryotes?
I. Simultaneous transcription and translation
II. Presence of intron sequences
III. Circular DNA - 🧠 ANSWER ✔✔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? - 🧠 ANSWER
✔✔Tryptophan
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,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? - 🧠 ANSWER ✔✔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 equilibrium, what is the proportion of carrier
individuals in this population? - 🧠 ANSWER ✔✔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? - 🧠 ANSWER ✔✔schwann cell
The cell bodies of afferent (sensory) nerves involved in somatic reflexes
are located in the - 🧠 ANSWER ✔✔Dorsal root ganglion
Rods and cones are associated with _____ and _____ vision, respectively.
- 🧠 ANSWER ✔✔Light/dark...color
Populations that are likely to be living at a density near the limit of their
resources, are characterized as - 🧠 ANSWER ✔✔K-selected
In many types of cancer, the function of the p53 gene is lost. Wild-type p53
is MOST likely to be a - 🧠 ANSWER ✔✔tumor suppressor
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
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,What glycolytic product is shuttled to the mitochondria in aerobic
respiration? - 🧠 ANSWER ✔✔Pyruvate
During human development, which process leads to the formation of three
germ layers? - 🧠 ANSWER ✔✔gastrulation
Telomerase is responsible for _____ the size of telomeres, and its function
is often ____ in carcinogenesis. - 🧠 ANSWER ✔✔maintaining ... increased
Which of the following is NOT a mode of natural selection? - 🧠 ANSWER
✔✔sexual selection
Protostomes have _____ and _____ types of cleavage. - 🧠 ANSWER
✔✔spiral ... determinate
Which of the following is NOT a characteristic of all chordates? - 🧠
ANSWER ✔✔vertebrae
In cardiac muscle, calcium ions can move freely between adjacent cells
through which of the following? - 🧠 ANSWER ✔✔gap junctions
Unlike most polypeptide hormones, steroid hormones are unique in that
they - 🧠 ANSWER ✔✔Diffuse across cell membranes
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
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PRIVACY STATEMENT. ALL RIGHTS RESERVED
, 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) - 🧠 ANSWER ✔✔cofactor
The order of normal blood flow through the human heart is - 🧠 ANSWER
✔✔right atrium, right ventricle, lungs, left atrium, left ventricle, body
Allopatric speciation refers to species formed after which type of
separation: - 🧠 ANSWER ✔✔geographic
Which two functional groups are always found in amino acids? - 🧠
ANSWER ✔✔Carboxyl and amine
Movement of ions across the membrane from higher to lower
concentrations through a channel protein is an example of - 🧠 ANSWER
✔✔Facilitated diffusion
Which group of plants has vascular tissue but does not produce seeds?
I. Mosses
II. Ferns
III. Gymnosperms - 🧠 ANSWER ✔✔II
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
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PRIVACY STATEMENT. ALL RIGHTS RESERVED
Questions and Answers 100%
Guaranteed Success | Already Rated A+
What enzyme does HIV use to convert RNA to DNA? - 🧠 ANSWER
✔✔Reverse Transcriptase
The promoter region of a prokaryotic gene is located ______ to the gene
and is the binding site for ______. - 🧠 ANSWER ✔✔5'...RNA polymerase
Which of the following is TRUE of prokaryotes?
I. Simultaneous transcription and translation
II. Presence of intron sequences
III. Circular DNA - 🧠 ANSWER ✔✔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? - 🧠 ANSWER
✔✔Tryptophan
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
1
PRIVACY STATEMENT. ALL RIGHTS RESERVED
,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? - 🧠 ANSWER ✔✔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 equilibrium, what is the proportion of carrier
individuals in this population? - 🧠 ANSWER ✔✔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? - 🧠 ANSWER ✔✔schwann cell
The cell bodies of afferent (sensory) nerves involved in somatic reflexes
are located in the - 🧠 ANSWER ✔✔Dorsal root ganglion
Rods and cones are associated with _____ and _____ vision, respectively.
- 🧠 ANSWER ✔✔Light/dark...color
Populations that are likely to be living at a density near the limit of their
resources, are characterized as - 🧠 ANSWER ✔✔K-selected
In many types of cancer, the function of the p53 gene is lost. Wild-type p53
is MOST likely to be a - 🧠 ANSWER ✔✔tumor suppressor
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
2
PRIVACY STATEMENT. ALL RIGHTS RESERVED
,What glycolytic product is shuttled to the mitochondria in aerobic
respiration? - 🧠 ANSWER ✔✔Pyruvate
During human development, which process leads to the formation of three
germ layers? - 🧠 ANSWER ✔✔gastrulation
Telomerase is responsible for _____ the size of telomeres, and its function
is often ____ in carcinogenesis. - 🧠 ANSWER ✔✔maintaining ... increased
Which of the following is NOT a mode of natural selection? - 🧠 ANSWER
✔✔sexual selection
Protostomes have _____ and _____ types of cleavage. - 🧠 ANSWER
✔✔spiral ... determinate
Which of the following is NOT a characteristic of all chordates? - 🧠
ANSWER ✔✔vertebrae
In cardiac muscle, calcium ions can move freely between adjacent cells
through which of the following? - 🧠 ANSWER ✔✔gap junctions
Unlike most polypeptide hormones, steroid hormones are unique in that
they - 🧠 ANSWER ✔✔Diffuse across cell membranes
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
3
PRIVACY STATEMENT. ALL RIGHTS RESERVED
, 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) - 🧠 ANSWER ✔✔cofactor
The order of normal blood flow through the human heart is - 🧠 ANSWER
✔✔right atrium, right ventricle, lungs, left atrium, left ventricle, body
Allopatric speciation refers to species formed after which type of
separation: - 🧠 ANSWER ✔✔geographic
Which two functional groups are always found in amino acids? - 🧠
ANSWER ✔✔Carboxyl and amine
Movement of ions across the membrane from higher to lower
concentrations through a channel protein is an example of - 🧠 ANSWER
✔✔Facilitated diffusion
Which group of plants has vascular tissue but does not produce seeds?
I. Mosses
II. Ferns
III. Gymnosperms - 🧠 ANSWER ✔✔II
COPYRIGHT©PROFFKERRYMARTIN 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
4
PRIVACY STATEMENT. ALL RIGHTS RESERVED
