Transcript Ch 12 Clicker Questions

CAMPBELL BIOLOGY IN FOCUS
URRY • CAIN • WASSERMAN • MINORSKY • REECE
12
The Chromosomal
Basis of Inheritance
Questions prepared by
Douglas Darnowski, Indiana University Southeast
James Langeland, Kalamazoo College
Murty S. Kambhampati, Southern University at New Orleans
Roberta Batorsky, Temple University
© 2016 Pearson Education, Inc.
SECOND EDITION
Why did the improvement of microscopy techniques in
the late 1800s set the stage for the emergence of modern
genetics?
A. It revealed new and unanticipated features of Mendel’s
pea plant varieties.
B. It allowed the study of meiosis and mitosis, revealing
parallels between behaviors of the Mendelian concept
of the gene and the movement/pairing of
chromosomes.
C. It allowed scientists to see the nucleotide sequence of
DNA.
D. It led to the discovery of mitochondria.
E. It showed genes functioning to direct the formation of
enzymes.
© 2016 Pearson Education, Inc.
Why did the improvement of microscopy techniques in
the late 1800s set the stage for the emergence of modern
genetics?
A. It revealed new and unanticipated features of Mendel’s
pea plant varieties.
B. It allowed the study of meiosis and mitosis,
revealing parallels between behaviors of the
Mendelian concept of the gene and the
movement/pairing of chromosomes.
C. It allowed scientists to see the nucleotide sequence of
DNA.
D. It led to the discovery of mitochondria.
E. It showed genes functioning to direct the formation of
enzymes.
© 2016 Pearson Education, Inc.
Morgan and his colleagues worked out a set of symbols to
represent fly genotypes. Which of the following are
representative?
A. AaBb  AaBb
B. 46 or 46w
C. w or w on X
D. 2  3
© 2016 Pearson Education, Inc.
Morgan and his colleagues worked out a set of symbols to
represent fly genotypes. Which of the following are
representative?
A. AaBb  AaBb
B. 46 or 46w
C. w or w on X
D. 2  3
© 2016 Pearson Education, Inc.
Imagine that Morgan had chosen a different organism
for his genetics experiments. What kind of species
would have made a better choice than fruit flies?
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Imagine that Morgan had used a grasshopper
(2n  24, and sex is determined as follows: male has X,
and female has XX) to study sex linkage. Predict where
the first mutant would have been discovered.
A.
B.
C.
D.
on the O chromosome of a male
on the X chromosome of a male
on the X chromosome of a female
on the Y chromosome of a male
© 2016 Pearson Education, Inc.
Imagine that Morgan had used a grasshopper
(2n  24, and sex is determined as follows: male has X,
and female has XX) to study sex linkage. Predict where
the first mutant would have been discovered.
A.
B.
C.
D.
on the O chromosome of a male
on the X chromosome of a male
on the X chromosome of a female
on the Y chromosome of a male
© 2016 Pearson Education, Inc.
Think about bees and ants, which have no X and Y sex
chromosomes. Males are haploid, whereas fertilization
results in females, as diploid cells become females. Which
of the following are accurate statements about bee and
ant males when they are compared to species in which
males are XY and diploid for the autosomes?
A. Bee males have half the DNA of bee females, whereas human
males have nearly the same amount of DNA that human females
have.
B. Considered across the genome, harmful (deleterious) recessives will
negatively affect bee males more than Drosophila males.
C. Human and Drosophila males have sons, but bee males do not.
D. Inheritance in bees is like inheritance of sex-linked characteristics in
humans.
E. none of the above
© 2016 Pearson Education, Inc.
Think about bees and ants, which have no X and Y sex
chromosomes. Males are haploid, whereas fertilization
results in females, as diploid cells become females. Which
of the following are accurate statements about bee and
ant males when they are compared to species in which
males are XY and diploid for the autosomes?
A. Bee males have half the DNA of bee females, whereas human
males have nearly the same amount of DNA that human
females have.
B. Considered across the genome, harmful (deleterious)
recessives will negatively affect bee males more than
Drosophila males.
C. Human and Drosophila males have sons, but bee males do not.
D. Inheritance in bees is like inheritance of sex-linked characteristics in
humans.
E. none of the above
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Determination of sex in Drosophila is similar to that in
humans. In some species of Drosophila, there are genes on
the Y chromosome that do not occur on the X
chromosome. Imagine that a mutation of one gene on the
Y chromosome reduces the size by half of individuals
with the mutation. Which of the following statements is
accurate with regard to this situation?
A. This mutation is transmitted to all offspring of a male with the
mutation.
B. This mutation is transmitted to all male but no female offspring of a
male with the mutation.
C. This mutation is transmitted to all offspring of a female with the
mutation.
D. This mutation is transmitted to all male but no female offspring of a
female with the mutation.
E. This mutation is transmitted to all offspring of both males and
females with the mutation.
© 2016 Pearson Education, Inc.
Determination of sex in Drosophila is similar to that in
humans. In some species of Drosophila, there are genes on
the Y chromosome that do not occur on the X
chromosome. Imagine that a mutation of one gene on the
Y chromosome reduces the size by half of individuals
with the mutation. Which of the following statements is
accurate with regard to this situation?
A. This mutation is transmitted to all offspring of a male with the
mutation.
B. This mutation is transmitted to all male but no female offspring
of a male with the mutation.
C. This mutation is transmitted to all offspring of a female with the
mutation.
D. This mutation is transmitted to all male but no female offspring of a
female with the mutation.
E. This mutation is transmitted to all offspring of both males and
females with the mutation.
© 2016 Pearson Education, Inc.
In cats, a sex-linked gene affects coat color. The O allele
produces an enzyme that converts eumelanin, a black or
brown pigment, into phaeomelanin, an orange pigment. The o
allele is recessive to O and produces a defective enzyme, one
that does not convert eumelanin into phaeomelanin. Which of
the following statements is/are accurate?
A.
B.
C.
D.
The phenotype of o-Y males is black/brown because the nonfunctional
allele o does not convert eumelanin into phaeomelanin.
The phenotype of OO and Oo males is orange because the functional
allele O converts eumelanin into phaeomelanin.
The phenotype of Oo males is mixed orange and black/brown because
the functional allele O converts eumelanin into phaeomelanin in some
cell groups (orange) and because in other cell groups the nonfunctional
allele o does not convert eumelanin into phaeomelanin.
The phenotype of O-Y males is orange because the nonfunctional allele
O does not convert eumelanin into phaeomelanin, while the phenotype
of o-Y males is black/brown because the functional allele o converts
eumelanin into phaeomelanin.
© 2016 Pearson Education, Inc.
In cats, a sex-linked gene affects coat color. The O allele
produces an enzyme that converts eumelanin, a black or
brown pigment, into phaeomelanin, an orange pigment. The o
allele is recessive to O and produces a defective enzyme, one
that does not convert eumelanin into phaeomelanin. Which of
the following statements is/are accurate?
A.
B.
C.
D.
The phenotype of o-Y males is black/brown because the
nonfunctional allele o does not convert eumelanin into
phaeomelanin.
The phenotype of OO and Oo males is orange because the functional
allele O converts eumelanin into phaeomelanin.
The phenotype of Oo males is mixed orange and black/brown because
the functional allele O converts eumelanin into phaeomelanin in some
cell groups (orange) and because in other cell groups the nonfunctional
allele o does not convert eumelanin into phaeomelanin.
The phenotype of O-Y males is orange because the nonfunctional allele
O does not convert eumelanin into phaeomelanin, while the phenotype
of o-Y males is black/brown because the functional allele o converts
eumelanin into phaeomelanin.
© 2016 Pearson Education, Inc.
Imagine a species with three loci thought to be on the
same chromosome. The recombination rate between locus
A and locus B is 35%, and the recombination rate
between locus B and locus C is 33%. Predict the
recombination rate between A and C.
A. The recombination rate between locus A and locus C
is either 2% or 68%.
B. The recombination rate between locus A and locus C
is probably 2%.
C. The recombination rate between locus A and locus C
is either 2% or 50%.
D. The recombination rate between locus A and locus C
is either 2% or 39%.
E. The recombination rate between locus A and locus C
cannot be predicted.
© 2016 Pearson Education, Inc.
Imagine a species with three loci thought to be on the
same chromosome. The recombination rate between locus
A and locus B is 35%, and the recombination rate
between locus B and locus C is 33%. Predict the
recombination rate between A and C.
A. The recombination rate between locus A and locus C
is either 2% or 68%.
B. The recombination rate between locus A and locus C
is probably 2%.
C. The recombination rate between locus A and locus
C is either 2% or 50%.
D. The recombination rate between locus A and locus C
is either 2% or 39%.
E. The recombination rate between locus A and locus C
cannot be predicted.
© 2016 Pearson Education, Inc.
Chromosomal rearrangements can occur after
chromosomes break. Which of the following statements is
most accurate with respect to alterations in chromosome
structure?
A. Chromosomal rearrangements are more likely to occur
in mammals than in other vertebrates.
B. Translocations and inversions are not deleterious
because no genes are lost in the organism.
C. Chromosomal rearrangements are more likely to occur
during mitosis than during meiosis.
D. An individual that is homozygous for a deletion of a
certain gene is likely to be more damaged than one
that is homozygous for a duplication of that same
gene because loss of a function can be lethal.
© 2016 Pearson Education, Inc.
Chromosomal rearrangements can occur after
chromosomes break. Which of the following statements is
most accurate with respect to alterations in chromosome
structure?
A. Chromosomal rearrangements are more likely to occur
in mammals than in other vertebrates.
B. Translocations and inversions are not deleterious
because no genes are lost in the organism.
C. Chromosomal rearrangements are more likely to occur
during mitosis than during meiosis.
D. An individual that is homozygous for a deletion of
a certain gene is likely to be more damaged than
one that is homozygous for a duplication of that
same gene because loss of a function can be
lethal.
© 2016 Pearson Education, Inc.
Imagine that you could create medical policy for a
country. In this country it is known that the frequency of
Down syndrome increases with increasing age of the
mother and that the frequency of schizophrenia and
autism increases with the age of the father. In both
schizophrenia and autism, the severity of characteristics
varies enormously and unpredictably among affected
individuals. Furthermore, financial resources are severely
limited, both for testing of pregnant women and for
supplemental training of children with Down syndrome.
What kind of policy regarding fetal testing would you
implement?
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Recall that in Drosophila, white eyes are due to an Xlinked recessive allele (Xw). Describe a genetic cross that
could result in white–eyed female Drosophila.
A.
B.
C.
D.
no possible cross
white-eyed females with red-eyed males
heterozygous red-eyed females with white-eyed males
heterozygous red-eyed females with red-eyed males
© 2016 Pearson Education, Inc.
Recall that in Drosophila, white eyes are due to an Xlinked recessive allele (Xw). Describe a genetic cross that
could result in white–eyed female Drosophila.
A. no possible cross
B. white-eyed females with red-eyed males
C. heterozygous red-eyed females with white-eyed
males
D. heterozygous red-eyed females with red-eyed males
© 2016 Pearson Education, Inc.
Which statement best describes the relationship between
recombination frequency and the physical distance of
genes on chromosomes?
A. There is no relationship. All genes have random
recombination frequencies.
B. There is no relationship. All genes have the same,
fixed recombination frequencies.
C. The farther apart two genes are, the higher the
recombination frequency
D. The closer together two genes are, the higher the
recombination frequency
© 2016 Pearson Education, Inc.
Which statement best describes the relationship between
recombination frequency and the physical distance of
genes on chromosomes?
A. There is no relationship. All genes have random
recombination frequencies.
B. There is no relationship. All genes have the same,
fixed recombination frequencies.
C. The farther apart two genes are, the higher the
recombination frequency
D. The closer together two genes are, the higher the
recombination frequency
© 2016 Pearson Education, Inc.
What is the expected recombination frequency for a
testcross between the black and cinnabar loci?
A.
B.
C.
D.
9%
48.5%
50%
57.5%
© 2016 Pearson Education, Inc.
What is the expected recombination frequency for a
testcross between the black and cinnabar loci?
A.
B.
C.
D.
9%
48.5%
50%
57.5%
© 2016 Pearson Education, Inc.
What is the expected recombination frequency for a
testcross between the black and brown loci?
A.
B.
C.
D.
48.5%
50%
56%
100%
© 2016 Pearson Education, Inc.
What is the expected recombination frequency for a
testcross between the black and brown loci?
A.
B.
C.
D.
48.5%
50%
56%
100%
© 2016 Pearson Education, Inc.
In tomatoes, a heterozygous plant with yellow flowers
and red fruit is crossed with a recessive plant having
white flowers and yellow fruit. The following distribution
of offspring is observed:
yellow flowers, red fruit
white flowers, yellow fruit
yellow flowers, yellow fruit
white flowers, red fruit
42.5%
42.5%
7.5%
7.5%
What conclusion can be made regarding the loci for
flower color and fruit color?
A. The loci may be on the same chromosome more than 50 map
units apart, or they may be on separate chromosomes.
B. The loci are on separate chromosomes.
C. The loci are on the same chromosome, at an unknown distance
from each other.
D. The loci are on the same chromosome 15 map units apart.
© 2016 Pearson Education, Inc.
In tomatoes, a heterozygous plant with yellow flowers
and red fruit is crossed with a recessive plant having
white flowers and yellow fruit. The following distribution
of offspring is observed:
yellow flowers, red fruit
white flowers, yellow fruit
yellow flowers, yellow fruit
white flowers, red fruit
42.5%
42.5%
7.5%
7.5%
What conclusion can be made regarding the loci for
flower color and fruit color?
A. The loci may be on the same chromosome more than 50 map
units apart, or they may be on separate chromosomes.
B. The loci are on separate chromosomes.
C. The loci are on the same chromosome, at an unknown distance
from each other.
D. The loci are on the same chromosome 15 map units apart.
© 2016 Pearson Education, Inc.
In tomatoes, a heterozygous plant with purple stems and
normal leaves is crossed with a recessive plant having
green stems and broad leaves. The following distribution
of offspring is observed:
purple stems, normal leaves
green stems, broad leaves
purple stems, broad leaves
green stems, normal leaves
25%
25%
25%
25%
What conclusion can be made regarding the loci for stem
color and leaf shape?
A. The loci may be on the same chromosome more than 50 map
units apart, or they may be on separate chromosomes.
B. The loci are on separate chromosomes.
C. The loci are on the same chromosome, at an unknown distance
from each other.
D. The loci are on the same chromosome 25 map units apart.
© 2016 Pearson Education, Inc.
In tomatoes, a heterozygous plant with purple stems and
normal leaves is crossed with a recessive plant having
green stems and broad leaves. The following distribution
of offspring is observed:
purple stems, normal leaves
green stems, broad leaves
purple stems, broad leaves
green stems, normal leaves
25%
25%
25%
25%
What conclusion can be made regarding the loci for stem
color and leaf shape?
A. The loci may be on the same chromosome more than 50
map units apart, or they may be on separate chromosomes.
B. The loci are on separate chromosomes.
C. The loci are on the same chromosome, at an unknown distance
from each other.
D. The loci are on the same chromosome 25 map units apart.
© 2016 Pearson Education, Inc.
Which of the following diagrams best depicts the
karyotype of a trisomy?
A.
B.
C.
D.
© 2016 Pearson Education, Inc.
Which of the following diagrams best depicts the
karyotype of a trisomy?
A.
B.
C.
D.
© 2016 Pearson Education, Inc.
Nondisjunction can happen in either meiosis I or meiosis
II. Consider an n + 1 gamete that is formed from
nondisjunction and compare the origin of the extra (+1)
chromosome between the two types of nondisjunction.
Select the best comparative statement.
A. There is no inherent difference between the two.
B. The +1 chromosome resulting from meiosis I nondisjunction
was a homolog of its partner, while that from meiosis II was
a sister chromatid of its partner.
C. The +1 chromosome resulting from meiosis I nondisjunction
was a sister chromatid of its partner, while that from
meiosis II was a homolog of its partner.
D. The +1 chromosome resulting from meiosis I nondisjunction
results in syndromes, while that from meiosis II does not.
© 2016 Pearson Education, Inc.
Nondisjunction can happen in either meiosis I or meiosis
II. Consider an n + 1 gamete that is formed from
nondisjunction and compare the origin of the extra (+1)
chromosome between the two types of nondisjunction.
Select the best comparative statement.
A. There is no inherent difference between the two.
B. The +1 chromosome resulting from meiosis I
nondisjunction was a homolog of its partner, while that
from meiosis II was a sister chromatid of its partner.
C. The +1 chromosome resulting from meiosis I nondisjunction
was a sister chromatid of its partner, while that from
meiosis II was a homolog of its partner.
D. The +1 chromosome resulting from meiosis I nondisjunction
results in syndromes, while that from meiosis II does not.
© 2016 Pearson Education, Inc.