USABO Practice Test
Questions and Complete
Solutions Graded 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
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
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
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
Which of the following is true for transport in xylem? - Answer: Movement through xylem depends
mainly on transpiration
Predation is considered a _________ interaction, while Mutualism is considered a ___________
interaction. - Answer: +/-, +/+
Which of the following organisms is INCORRECTLY paired with its trophic level? - Answer: Beetle -
secondary consumer
Which of the following is an example of habituation? - Answer: Hydra initially contract when gently
touched, but soon stop responding.
Suppose gene "C" is the gene for color. Its dominant allele has the effect of allowing the production of
fur color while its recessive allele interrupts color production. At another locus, there exists another
gene that influences color, at which black (B) is dominant to brown (b). What is the relationship between
these genes called? - Answer: Epistatic
Questions and Complete
Solutions Graded 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
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
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
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
Which of the following is true for transport in xylem? - Answer: Movement through xylem depends
mainly on transpiration
Predation is considered a _________ interaction, while Mutualism is considered a ___________
interaction. - Answer: +/-, +/+
Which of the following organisms is INCORRECTLY paired with its trophic level? - Answer: Beetle -
secondary consumer
Which of the following is an example of habituation? - Answer: Hydra initially contract when gently
touched, but soon stop responding.
Suppose gene "C" is the gene for color. Its dominant allele has the effect of allowing the production of
fur color while its recessive allele interrupts color production. At another locus, there exists another
gene that influences color, at which black (B) is dominant to brown (b). What is the relationship between
these genes called? - Answer: Epistatic
