AP BIO EXAM GENETICS QUESTIONS
AND ANSWERS
In humans, red-green color blindness is a sex-linked recessive trait. If a man and a
woman produce a color-blind son, which of the following must be true?
-Both parents carry the allele color blindness
-The father carries the allele for color blindness
-The father is color-blind
-Neither parent carries the allele for color blindness
-The mother carries the allele for color blindness - Correct Answers -The mother carries
the allele for color blindness
Arctic foxes typically have a white coat in the winter. In summer, when there is no snow
on the ground, the foxes typically have a darker coat. Which fo the following is most
likely responsible fo rate seasonal change in coat-color?
-The decrease in the amount of daylight in winter causes a change in gene expression,
which results in the foxes growing a lighter-appearing coat.
-The diet of the foxes in summer lacks a particular nutrient, which causes the foxes to
lose their white coat and grow a darker-colored coat.
-Competition for mates int he's print causes each fox to increase its camouflage with the
environment by producing a darker-appearing coat.
-The lower temperatures in winter denature the pigment molecules in the arctic fox coat,
causing the coat to become lighter in color - Correct Answers -The decrease in the
amount of daylight in winter causes a change in gene expression, which results in the
foxes growing a lighter-appearing coat
In a species that has five different alleles for a gene at a particular locus, how many
different alleles may be present in the somatic cells of one diploid individual?
-two
-four
-three
-five
-one - Correct Answers –two
The F1 offspring of Mendel's classic pea cross always looked like one of the two
parental varieties because
, -the traits blended together during fertilization
-one phenotype was completely dominant over another
-each allele affected phenotypic expression
-different genes interacted to produce the parental phenotype
-no genes interacted to produce the parental phenotype - Correct Answers -one
phenotype was completely dominant over another
Coat color in mice is determined by genes on two loci. When black mice from a
particular population mate, they produce offspring in the following ratios 9 black: 3
brown: 4 white. These results suggest a th white coat color is expressed as a result of
-a sex-linked trait
-dominance
-incomplete dominance
-epistasis
-codominance - Correct Answers -epistasis
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long
tails (t). What fraction of the progeny of the cross BbTt x Bbtt will have black fur and
long tails?
-3/8
-9/16
-1/2
-3/16
-1/16 - Correct Answers -3/8
Two types of cholesterol transport proteins, low-density lipoproteins (LDL) and high-
density hippo proteins (HDL), bind to cholesterol and carry it through the bloodstream.
Familial hypercholesterolemia (FH) is characterized by high cholesterol levels in the
blood, which can lead to cardiovascular disease.
FH is associated with a loss-of-function mutation of a gene that encodes LDL receptors
in liver cells. Individuals who are heterozygous produce lower-than normal amount of
the LDL receptors, and individuals who are homozygous fo the mutant allele have no
LDL receptor function.
Individuals with FH can be treated with drugs that result in increased production of LDL
receptors in liver cells. Which of the following best explains the observation that the
drugs can effectively control blood cholesterol levels in individuals who are
heterozygous but are not effective in individuals homozygous for the mutant allele.
- - Correct Answers -There must be at least one copy of the wild-type LDL receptor
allele to produce functional LDL receptors
Hydrangea macrophylla is a species of plant with blue or pink flowers. Flower color in
theses plants is thought to be determined primarily by soil conditions rather than by
AND ANSWERS
In humans, red-green color blindness is a sex-linked recessive trait. If a man and a
woman produce a color-blind son, which of the following must be true?
-Both parents carry the allele color blindness
-The father carries the allele for color blindness
-The father is color-blind
-Neither parent carries the allele for color blindness
-The mother carries the allele for color blindness - Correct Answers -The mother carries
the allele for color blindness
Arctic foxes typically have a white coat in the winter. In summer, when there is no snow
on the ground, the foxes typically have a darker coat. Which fo the following is most
likely responsible fo rate seasonal change in coat-color?
-The decrease in the amount of daylight in winter causes a change in gene expression,
which results in the foxes growing a lighter-appearing coat.
-The diet of the foxes in summer lacks a particular nutrient, which causes the foxes to
lose their white coat and grow a darker-colored coat.
-Competition for mates int he's print causes each fox to increase its camouflage with the
environment by producing a darker-appearing coat.
-The lower temperatures in winter denature the pigment molecules in the arctic fox coat,
causing the coat to become lighter in color - Correct Answers -The decrease in the
amount of daylight in winter causes a change in gene expression, which results in the
foxes growing a lighter-appearing coat
In a species that has five different alleles for a gene at a particular locus, how many
different alleles may be present in the somatic cells of one diploid individual?
-two
-four
-three
-five
-one - Correct Answers –two
The F1 offspring of Mendel's classic pea cross always looked like one of the two
parental varieties because
, -the traits blended together during fertilization
-one phenotype was completely dominant over another
-each allele affected phenotypic expression
-different genes interacted to produce the parental phenotype
-no genes interacted to produce the parental phenotype - Correct Answers -one
phenotype was completely dominant over another
Coat color in mice is determined by genes on two loci. When black mice from a
particular population mate, they produce offspring in the following ratios 9 black: 3
brown: 4 white. These results suggest a th white coat color is expressed as a result of
-a sex-linked trait
-dominance
-incomplete dominance
-epistasis
-codominance - Correct Answers -epistasis
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long
tails (t). What fraction of the progeny of the cross BbTt x Bbtt will have black fur and
long tails?
-3/8
-9/16
-1/2
-3/16
-1/16 - Correct Answers -3/8
Two types of cholesterol transport proteins, low-density lipoproteins (LDL) and high-
density hippo proteins (HDL), bind to cholesterol and carry it through the bloodstream.
Familial hypercholesterolemia (FH) is characterized by high cholesterol levels in the
blood, which can lead to cardiovascular disease.
FH is associated with a loss-of-function mutation of a gene that encodes LDL receptors
in liver cells. Individuals who are heterozygous produce lower-than normal amount of
the LDL receptors, and individuals who are homozygous fo the mutant allele have no
LDL receptor function.
Individuals with FH can be treated with drugs that result in increased production of LDL
receptors in liver cells. Which of the following best explains the observation that the
drugs can effectively control blood cholesterol levels in individuals who are
heterozygous but are not effective in individuals homozygous for the mutant allele.
- - Correct Answers -There must be at least one copy of the wild-type LDL receptor
allele to produce functional LDL receptors
Hydrangea macrophylla is a species of plant with blue or pink flowers. Flower color in
theses plants is thought to be determined primarily by soil conditions rather than by
