Deck 4: The Chromosome Theory of Inheritance

Question 1

During which of the following stages of the cell cycle would a chromosome consist of only a single chromatid?

A)G₁
B)G₂
C)mitotic prophase
D)mitotic metaphase
E)All of the choices are correct.

Answer 1

A

Question 2

The cells that undergo meiosis in males are

A)spermatocytes.
B)spermatogonia.
C)spermatids.
D)oocytes.
E)sperm.

Answer 2

A

Question 3

Microtubules that originate at opposite centrosomes and interdigitate near the cell's equator without attaching to chromosomes are the

A)kinetochore microtubules.
B)polar microtubules.
C)astral microtubules.
D)interdigitating microtubules.

Answer 3

B

Question 4

Crossing-over between homologous chromosomes occurs at which of the following stages of meiosis?

A)S phase
B)prophase I
C)metaphase I
D)anaphase I
E)prophase II

Question 5

Nondisjunction can occur at either the first or second division of meiosis.XXY individuals could arise from nondisjunction at the ________ meiotic division in the ________.

A)first; mother
B)second; mother
C)first; father
D)second; father
E)More than one of the choices could give rise to XXY individuals.

Question 6

The stage of mitosis when sister chromatids separate from each other and migrate to opposite poles of a cell is called

A)interphase.
B)prophase.
C)metaphase.
D)anaphase.
E)telophase.

Question 7

A chromosome with two arms of similar length is referred to as

A)acrocentric.
B)homologous.
C)telocentric.
D)metazoan.
E)metacentric.

Question 8

The chromosomal structure to which spindle fibers attach during the mitotic divisions is the

A)chromatid.
B)centrosome.
C)kinetochore.
D)metaphase plate.
E)centromere.

Question 9

In Drosophila virilis, somatic cell nuclei contain 12 chromosomes while sperm nuclei contain only 6 chromosomes.What does n equal for this species?

A)3
B)6
C)12
D)24
E)6 or 12, depending on cell type

Question 10

Mitosis results in ________ chromosome number, whereas meiosis results in ________ chromosome number.

A)a doubling of; no change in
B)no change in; no change in
C)a reduction by half in; no change in
D)no change in; a doubling of
E)no change in; a reduction by half in

Question 11

Which types of chromosomes provide the basis for sex determination in most mammals?

A)haploid set of chromosomes
B)diploid set of chromosomes
C)autosomes
D)sex chromosomes
E)homologous chromosomes

Question 12

Premeiotic germ cells that divide mitotically in females are

A)primary oocytes.
B)secondary oocytes.
C)ootids.
D)oogonia.
E)ova.

Question 13

The mitotic stage during which chromosomes begin attaching to spindle fibers and moving randomly and reversibly to the centrosomes is

A)prophase.
B)prometaphase.
C)metaphase.
D)anaphase.
E)telophase.

Question 14

Which of the following events occurs during mitosis but not during meiosis?

A)Sister chromatids segregate.
B)Homologous chromosomes pair.
C)Crossing-over occurs between homologous chromosomes.
D)Chromosomes align on the metaphase plate.
E)None of the choices is correct.

Question 15

Humans have 22 pairs of autosomes plus one sex chromosome pair.How many autosomes are present in a normal human primary spermatocyte?

A)22
B)23
C)44
D)45
E)46

Question 16

Nondisjunction can occur at either the first or second division of meiosis.XYY individuals would most likely arise from nondisjunction at the ________ meiotic division in the ________.

A)first; mother
B)second; mother
C)first; father
D)second; father
E)More than one of the choices could give rise to XYY individuals.

Question 17

The stage of mitosis when chromosomes condense to form rod-shaped structures visible under the microscope is called

A)interphase.
B)prophase.
C)metaphase.
D)anaphase.
E)telophase.

Question 18

Drosophila melanogaster has four pairs of chromosomes (including a pair of sex chromosomes).Sperm from this species are formed by a meiotic process in which homologous chromosomes pair and segregate but do not undergo crossing-over.How many genetically different kinds of sperm could be produced by a Drosophila melanogaster male (XY)?

A)4
B)8
C)16
D)64
E)256

Question 19

At which of the following stages of meiosis would homologous chromosomes be paired?

A)prophase of meiosis I
B)both prophase of meiosis I and prophase of meiosis II
C)metaphase of meiosis I
D)metaphase of meiosis II
E)both prophase of meiosis I and metaphase of meiosis I

Question 20

Which of the following statements applies to homologous nonsister chromatids?

A)Their centromeres are attached during meiosis II.
B)They are genetically identical.
C)They segregate from each other at anaphase of mitosis.
D)They contain the same genes in the same order but may have different alleles of some genes.
E)More than one statement applies to homologous chromatids.

Question 21

Normal fruit flies have red eyes.Flies with mutations that block the function of the X-linked white gene have white eyes.The wild-type allele is completely dominant to mutant alleles.A white-eyed female fruit fly is mated to a red-eyed male.One of their hundreds of female progeny is white-eyed.This white-eyed daughter likely arose from nondisjunction of the sex chromosomes during ________ in the ________.

A)meiosis I; mother
B)meiosis II; mother
C)meiosis I; father
D)meiosis II; father
E)meiosis I or II; mother

Question 22

In fruit flies, brown eyes can be caused by recessive mutant alleles of any one of three genes: pn (prune), bw (brown)or ry (rosy).The pn gene is X-linked, bw is on the second chromosome, and ry is on the third chromosome.One wild-type allele of each of the three genes must be present for eyes to be red (wild type).Suppose that two brown-eyed flies are crossed and their progeny consist of brown-eyed sons and red-eyed daughters.Which mutation is responsible for the brown eyes in the parental female?

A)pn
B)bw
C)ry
D)either bw or ry
E)any of the three-pn, bw, or ry

Question 23

In chickens, females have two different sex chromosomes (Z and W), while the males have two Z chromosomes.A Z-linked gene controls the pattern of the feathers, with the dominant B allele causing the barred pattern and the b allele causing nonbarred feathers.Which of the following crosses would produce all daughters of one type (barred or nonbarred)and all sons of the other type?

A)barred females × nonbarred males
B)nonbarred females × barred males
C)nonbarred females × nonbarred males
D)barred females × barred males
E)More than one of the choices is correct.

Question 24

What aspect of chromosome behavior most clearly accounts for Mendel's law of segregation?

A)movement of sister chromatids to opposite poles at anaphase II of meiosis
B)movement of homologous chromosomes to opposite poles at anaphase I of meiosis
C)crossing-over between homologous chromosomes during prophase I of meiosis
D)replication of chromosomes prior to meiosis
E)independent alignment of different homologous pairs on the metaphase I spindle

Question 25

In the following pedigree, the indicated trait is most likely caused by which type of allele?

A)autosomal recessive
B)autosomal dominant
C)X-linked recessive
D)X-linked dominant
E)Y-linked

Question 26

Males with one copy of an X-linked gene are said to be ________ for that gene.

A)homozygous
B)heteroallelic
C)heterozygous
D)hemizygous
E)deficient

Question 27

Cells in the G₀ stage

A)have two chromatids per chromosome.
B)are replicating their chromosomes.
C)are about to enter the mitotic phase of the cell cycle.
D)are in an extended G₁ phase and no longer dividing.
E)are dead.

Question 28

Suppose you discover a mouse that has spiky fur instead of the usual soft fur.You notice that this trait seems to be present only in males.To investigate this pattern, you cross a spiky-fur male with a soft-fur female, and find that all the F₁ progeny of both sexes have soft fur.You then interbreed the F₁ and observe that all the F₂ females have soft fur, but 1/4 of the F₂ males have spiky fur.You conclude that the spiky allele is

A)an X-linked recessive.
B)Y-linked.
C)autosomal recessive with sex-influenced expression.
D)an X-linked dominant.
E)an autosomal dominant with sex-influenced expression.

Question 29

Red-green color blindness is controlled by an X-linked gene in humans.The allele that causes color blindness is recessive to the allele for normal vision.A man and woman both with normal vision had color-blind fathers.If this man and woman have a child, what is the probability that the child will be color blind?

A)1/2
B)1/4
C)1/8
D)1/3
E)0

Question 30

Hemophilia is caused by an X-linked recessive mutation in humans.If a woman whose paternal uncle (father's brother)was a hemophiliac marries a man whose brother is also a hemophiliac, what is the probability that their first child will have hemophilia? (Assume that no other cases of hemophilia and no hidden carriers exist in the pedigree. )

A)0
B)1/4
C)1/2
D)1/8
E)1

Question 31

Which of the following is not a property of homologous chromosomes?

A)They pair physically during prophase of meiosis I.
B)They exchange genes by crossing over during meiosis.
C)They carry alleles for the same genes at the same chromosomal position.
D)Their centromeres are attached to each other during G₂ of the cell cycle.
E)They segregate to opposite poles at anaphase of meiosis I.

Question 32

Cells in the G₂ stage of the cell cycle have ________ as cells of the same species in the G₁ stage.

A)twice as many crossovers
B)twice as many chromatids
C)half as many chromatids
D)the same number of chromatids
E)half as many chromosomes

Question 33

A variable trait in corn is the presence or absence of knobs at particular sites on some chromosomes.The allele present on each chromosome determines whether or not that chromosome has a knob.Suppose that one member of each of two pairs of homologs in a corn plant has a knob.If this plant is crossed with a knobless plant, what percentage of the offspring is expected to have only knobless chromosomes?

A)100%
B)75%
C)50%
D)25%
E)0%

Question 34

Which aspect(s)of chromosome behavior is/are primarily responsible for the tremendous amount of genetic variability associated with sexual reproduction?

A)segregation of sister chromatids at anaphase II of meiosis
B)segregation of homologous chromosomes at anaphase I of meiosis
C)crossing-over between homologous chromosomes during prophase I of meiosis
D)independent alignment of different homologous pairs on the metaphase I spindle
E)both crossing-over between homologous chromosomes during prophase I of meiosis and independent alignment of different homologous pairs on the metaphase I spindle

Question 35

Suppose you discover a new species of worm that exists in two forms-slimy and nonslimy.You find that mating slimy females to nonslimy males produces offspring consisting of slimy males and nonslimy females, whereas mating nonslimy females with slimy males produces offspring of both sexes that are all slimy.You would conclude that the ________ allele is dominant and that ________ are the heterogametic sex (the sex with two different sex chromosomes)in this species of worm.

A)slimy; females
B)slimy; males
C)nonslimy; females
D)nonslimy; males

Question 36

Normal fruit flies have red eyes.Flies with mutations that block the function of the X-linked white gene have white eyes.The wild-type allele is completely dominant to mutant alleles.A white-eyed female fruit fly is mated to a red-eyed male.One of their hundreds of female progeny is white-eyed.What is the likely karyotype of this white-eyed daughter?

A)XX
B)XXY
C)XO
D)XXX
E)XYY

Question 37

Which sex chromosomes are present in only one sex?

A)X and Z
B)X and W
C)Y and Z
D)Y and W
E)X and Y

Question 38

What aspect of chromosome behavior most clearly accounts for Mendel's law of independent assortment?

A)movement of sister chromatids to opposite poles at anaphase II of meiosis
B)movement of homologous chromosomes to opposite poles at anaphase I of meiosis
C)crossing over between homologous chromosomes during prophase I of meiosis
D)replication of chromosomes prior to meiosis
E)independent alignment of different homologous pairs on the metaphase I spindle

Question 39

Normal fruit flies have red eyes.Flies with mutations that block the function of the X-linked white gene have white eyes.The wild-type allele is completely dominant to mutant alleles.A cross between a white-eyed female fruit fly and a red-eyed male would generate which of the following types of progeny?

A)red-eyed females and white-eyed males
B)white-eyed females and red-eyed males
C)all red-eyed females and a 50:50 mixture of white-eyed and red-eyed males
D)all red-eyed males and a 50:50 mixture of white-eyed and red-eyed females
E)The result cannot be predicted because it depends on whether the female is homozygous or heterozygous.

Question 40

Color vision depends on dominant alleles of three different genes: the R gene and the G gene, both on the X chromosome, and the B gene, which is autosomal.Recessive mutant alleles of any one of these three genes can cause color blindness in homozygotes.Suppose a color-blind man marries a color-blind woman and all their offspring have normal vision.What is the genotype of the woman?

A)RR GG bb
B)RR gg BB
C)rr GG bb
D)RR gg BB or RR GG bb
E)rr GG bb or rr gg BB

Question 41

In animal gametogenesis, a single primary spermatocyte generates ________ sperm, while a single primary oocyte generates ________ egg(s).

A)1; 4
B)1; 1
C)4; 2
D)4; 1
E)4; 4

Question 42

In humans, XO individuals are females with Turner syndrome and XXY individuals are males with Klinefelter syndrome.Red-green color blindness is caused by an X-linked recessive allele.Suppose a color-blind man and a woman with normal vision and no family history of color blindness married and had a daughter who was color blind and had Turner syndrome.Which event could have given rise to this offspring?

A)nondisjunction at meiosis I in the mother
B)nondisjunction at meiosis II in the mother
C)nondisjunction at meiosis I in the father
D)nondisjunction at meiosis II in the father
E)nondisjunction at either meiosis I or meiosis II in the mother

Question 43

In human oogenesis, how many chromosomes does a primary oocyte carry?

A)22
B)23
C)44
D)46
E)92

Question 44

What is the correct order of these meiotic events? A Segregation of homologous chromosomes to opposite poles.
B Segregation of sister chromatids to opposite poles.
C Alignment of homologous pairs on the midplate of the cell.
D Pairing and synapsis of homologous chromosomes.
E Condensation of chromosomes in a diploid nucleus.

A)CDEAB
B)DCEBA
C)EDCBA
D)EDCAB
E)DCABE

Question 45

In human oogenesis, how many chromosomes does a secondary oocyte carry?

A)22
B)23
C)44
D)46
E)92

Question 46

In the following pedigree, the indicated trait is most likely caused by which type of allele?

A)autosomal recessive
B)autosomal dominant
C)X-linked recessive
D)X-linked dominant
E)Y-linked

Question 47

In fruit flies, an X-linked dominant mutant allele of the Notch gene (N)causes Notched wings in heterozygous females but is lethal in hemizygous or homozygous condition.What ratio of offspring would be observed in a cross of a Notched-wing female with a normal male?

A)1/3 Notched-wing females, 1/3 normal females, 1/3 normal males
B)1/4 Notched-wing females, 1/4 normal females, 1/4 Notched-wing males, 1/4 normal males
C)1/2 Notched-wing females, 1/2 normal males
D)1/2 normal females, 1/2 Notched-wing males
E)2/3 Notched-wing females, 1/3 normal males

Question 48

In the following pedigree, the indicated trait is caused by what type of allele?

A)autosomal recessive
B)autosomal dominant
C)X-linked recessive
D)X-linked dominant
E)Y-linked

Question 49

A diploid cell with three pairs of chromosomes has the genotype Aa Bb Cc, where each gene is on a different chromosome.If this cell were to undergo meiotic division, how many genetically different types of gametes could be produced?

A)1
B)3
C)6
D)8
E)9

Question 50

In which of the following cases will a Barr body be seen?

A)only XX
B)XY
C)XO
D)only XXY
E)both XX and XXY

Question 51

You engineer an XY mouse in which the SRY gene is inactivated.What do you expect to observe in this mouse?

A)The mouse will develop male anatomic features.
B)The mouse will develop female anatomic features.
C)The mouse's Y chromosome will convert into an X chromosome.
D)The mouse's X chromosome will convert into a Y chromosome.
E)The mouse will exhibit both male and female morphological features.

Question 52

Individuals with an XXY karyotype are ________ in humans and ________ in fruit flies.

A)male; male
B)male; female
C)female; male
D)female; female
E)male; intersexual

Question 53

An XY individual with a loss-of-function mutation in the SRY gene is expected to be female.

Question 54

In the following pedigree, the indicated trait is most likely caused by which type of allele?

A)autosomal recessive
B)autosomal dominant
C)X-linked recessive
D)X-linked dominant
E)Y-linked

Question 55

In humans, XO individuals are females with Turner syndrome and XXY individuals are males with Klinefelter syndrome.Which of the following events cannot give rise to a Klinefelter male?

A)nondisjunction at meiosis I in the mother
B)nondisjunction at meiosis II in the mother
C)nondisjunction at meiosis I in the father
D)nondisjunction at meiosis II in the father
E)All of the choices could give rise to a Klinefelter male.

Question 56

A cell with three pairs of chromosomes has the genotype Aa Bb Cc, with each locus on a different chromosome.If this cell were to undergo mitotic division, how many genetically different types of daughter cells could be produced?

A)1
B)3
C)6
D)8
E)9

Question 57

You examine cells with a microscope and detect two Barr bodies in each cell.What is the most likely genotype of the cells?

A)XX
B)XY
C)XO
D)XXY
E)XXX

Question 58

In the following pedigree, the indicated trait most likely is caused by which type of allele?

A)autosomal recessive
B)autosomal dominant
C)X-linked recessive
D)X-linked dominant
E)Y-linked

Question 59

What is the correct order of these mitotic events? A Chromosomes align on the midplate of the cell.
B Kinetochores begin attaching to spindle fibers.
C Nuclear membrane reforms and chromosomes decondense.
D Chromosomes condense and centrosomes migrate to opposite sides of nucleus.
E Sister chromatids separate and move to opposite poles.

A)BDACE
B)DABEC
C)DBAEC
D)ABDCE
E)EDBAC

Question 60

In human oogenesis, how many chromosomes does an oogonium carry?

A)22
B)23
C)44
D)46
E)92

Question 61

Individuals with Turner syndrome have which of the following sex chromosome complements?

A)XO
B)XX
C)XYY
D)XXY
E)XXX

Question 62

Germ-line cells are haploid but gametes are diploid.

Question 63

Structures that appear along the synaptonemal complex during pachytene where genetic material is exchanged between nonsister chromatids are the ________.

A)chiasmosomes
B)telomeres
C)centromeres
D)recombination nodules
E)kinetochores

Question 64

The period between meiosis I and II is termed interkinesis.

Question 65

Crossing-over allows the reassortment of linked genes.

Question 66

Crossing-over occurs in meiosis I and meiosis II.

Question 67

At which phase of the cell cycle are sister chromatids generated?

A)G₀
B)G₁
C)G₂
D)S
E)M

Question 68

Which term describes chromosomes whose centromeres are located closer to one end of the chromosome?

A)metacentric
B)acrocentric
C)holocentric
D)anacentric

Question 69

Cytokinesis in plant cells occurs by means of a cleavage furrow.

Question 70

Orientation of each chromosomal pair on the spindle axis is random.

Question 71

Which of the following is a diploid cell destined for a specialized role in the production of gametes?

A)somatic cell
B)germ-line cell
C)spermatid
D)polar body
E)ootid

Question 72

Which of the following statements is FALSE?

A)Sister chromatids of the same chromosome are identical.
B)Sister chromatids can be nonhomologous chromosomes.
C)Homologous chromosomes are not necessarily identical.
D)An example of a nonhomologous chromosome pair is paternal chromosome 1 and paternal chromosome 2 in a human.

Question 73

Crossing-over occurs during prophase I of meiosis.

Question 74

The domestic dog has 39 pairs of homologous chromosomes.A dog's somatic cells have ________ chromosomes and gametes have ________ chromosomes.

A)78; 78
B)78; 39
C)39; 15
D)156; 78
E)39; 39

Question 75

Suppose you discovered a new mutation in mice that causes a curved spine.You noticed that this mutant phenotype is present only in females.When curved-spine females are crossed with normal males, the progeny are always recovered in a 1:1:1 ratio of curved-spine females, normal females, and normal males.Explain the genetic basis for this ratio.

A)hemizygous or homozygous lethal autosomal allele
B)hemizygous or homozygous lethal sex-linked allele
C)recessive sex-linked allele
D)recessive autosomal allele
E)dominant sex-linked allele

Question 76

In human oogenesis, how many chromosomes does an ovum carry?

A)22
B)23
C)44
D)46
E)92

Question 77

At the end of meiosis I, each daughter cell contains the sister chromatids from only one chromosome from each chromosomal pair.

Question 78

DNA replication occurs in mitosis.

Question 79

Mitosis and cytoplasmic division result in the formation of two genetically identical cells.

Question 80

The region where the homologous chromosomal pairs align is the metaphase plate.