Deck 12: Chromosomal Basis of Inheritance

Question 1

A litter produced by a calico cat is not expected to include

A)solid-colored female kittens.
B)calico female kittens.
C)solid-colored male kittens.
D)calico male kittens.
E)Any of these

Answer 1

D

Question 2

Red-green color blindness in humans is an X-linked recessive trait.What will the progeny ratios be if a carrier female is mated with a normal male?

A)All the sons will be color blind; all the daughters will be normal.
B)All the sons and half the daughters will be color blind.
C)Half the sons will be color blind; all the daughters will be carriers.
D)Half the sons will be color blind; half the daughters will be carriers.
E)All the sons and all the daughters will be normal.

Answer 2

D

Question 3

Chromosomes with only one arm are known as

A)metacentric.
B)submetacentric.
C)acrocentric.
D)telocentric.
E)acentric.

Answer 3

D

Question 4

Individuals with Turner syndrome are

A)euploid.
B)aneuploid.
C)polyploid.
D)haploid.
E)monoploid.

Question 5

Which of the following organisms has a ZZ-ZW method of sex determination?

A)House mice
B)Monarch butterflies
C)Fruit flies
D)Humans
E)Worms

Question 6

The largest human autosome is chromosome ________ and the smallest is chromosome ________.

A)1,22
B)1,21
C)1,Y
D)X,22
E)None of these

Question 7

Plants that produce separate male and female flowers are said to be

A)hermaphroditic.
B)heterosexual.
C)monoecious.
D)dioecious.
E)homosexual.

Question 8

Which of the following is an example of genetic mosaicism?

A)Calico coat color in cats
B)Albinism in mice
C)Male pattern baldness in humans
D)Red-green color blindness in humans
E)White eyes in Drosophila

Question 9

Cells obtained from a Triplo-X woman would contain ________ Barr bodies.

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

Question 10

A human male who undergoes a sex-change operation will be chromosomally

A)XX.
B)XY.
C)XXY.
D)XYY.
E)YYY.

Question 11

A person with an XO genotype for the sex chromosomes would be phenotypically

A)male.
B)female.
C)intersex (both male and female).
D)male or female with equal probability.
E)neither male nor female.

Question 12

The chromosome theory of inheritance states that

A)genes are located on chromosomes.
B)chromosomes replicate before cell division.
C)alleles of a gene segregate during cell division.
D)chromosomes consist of DNA.
E)different chromosomes assort independently of one another.

Question 13

In an organism with 16 chromosomes per cell,how many DNA molecules are present in a cell undergoing anaphase of mitosis?

A)8
B)16
C)24
D)32
E)64

Question 14

Synaptonemal complex forms during

A)leptonema.
B)zygonema.
C)pachynema.
D)diplonema.
E)diakinesis.

Question 15

The spindle fibers attach to the centromere via a protein complex called

A)tubulins.
B)microtubules.
C)chromatid.
D)kinetochore.
E)chiasma.

Question 16

In human males,genes on the X chromosome are

A)homozygous.
B)heterozygous.
C)homogametic.
D)heterogametic.
E)hemizygous.

Question 17

The key gene in mammalian sex determination is

A)the testis-determining factor gene.
B)the Y-factor gene.
C)the holandric factor gene.
D)the X-inactivation center.
E)the lyonization gene.

Question 18

Phenotypically,a female (XX)mouse embryo that was transformed with a small piece of a Y chromosome bearing the SRY gene would develop as

A)a male.
B)a female.
C)an intersex individual.
D)a male initially,then revert to female after birth.
E)a female initially,then revert to male after birth.

Question 19

In butterflies,males are the ________ sex.

A)homozygous
B)heterozygous
C)homogametic
D)heterogametic
E)hemizygous

Question 20

Which of the following statements is not true?

A)Many plants exhibit alternation between haploid and diploid stages.
B)Chromosome number is generally constant within groups of organisms with common ancestry.
C)The Y-bearing sex is known as the heterogametic sex.
D)Sex determination is chromosomal in some organisms and genic in others.
E)The sex chromosome systems of birds and mammals are likely to have evolved independently.

Question 21

The chromosome theory of inheritance sought to explain Mendelian patterns in terms of chromosome movement.Can you think of an experimental approach to test for the Mendelian principle of segregation using chromosomes?

Question 22

A woman who is heterozygous for the hemophilia allele has a 100% chance of having an affected son.

Question 23

How did chromosomes get their name?

Question 24

The centrioles are highly conserved chromosome regions that interact with spindle fibers during cell division.

Question 25

What are the differences between metaphase I and metaphase II of meiosis?

Question 26

In flowering plants,gametes are produced mitotically from spores.

Question 27

X-linked or sex-linked traits are expressed in males but not in females.

Question 28

Barr bodies are inactivated X chromosomes.

Question 29

X-linked traits are more likely to be expressed in males.Why? Under what circumstances are they expressed in females?

Question 30

Nondisjunction can lead to two forms of aneuploidy.What are they,and how do they occur?

Question 31

Half a woman's somatic cells express her paternal X chromosome and half express her maternal X chromosome.

Question 32

Synapsis usually forms between nonsister chromatids.

Question 33

Why will a human embryo develop as a male in the presence of a Y chromosome,regardless of the number of X chromosomes present?

Question 34

A woman who is color blind,a sex-linked trait,has several children with a man who has normal vision.What are the possible phenotypes of their children with respect to this trait?

Question 35

Describe two dosage compensation mechanisms found in animals.

Question 36

Some cells may exit the cell cycle and enter a nondividing G₀ state.

Question 37

What is the connection between the work of Mary Lyon and Murray Barr?

Question 38

Nondisjunction is the failure of sex chromosomes to separate during gamete formation.

Question 39

A person with two X chromosomes is the homogametic sex.

Question 40

Closely related species,like chimpanzees and humans,often differ in chromosome number by only one or two chromosomes,suggesting that chromosomes can experience fission and fusion over evolutionary time.Can you think of a way to test this?

Question 41

Drosophila fruit flies,like mammals,have an X-Y sex-determination system.The insect differs from the mammalian system in an important respect,however.What is it?

Question 42

What pattern of expression is expected for an X-linked dominant trait like hereditary enamel hypoplasia?

Question 43

Describe Calvin Bridges's classic study of nondisjunction of sex chromosomes,which provided support for the chromosome theory of inheritance.

Question 44

You are a breeder of animals with an X-linked coat-color gene,one allele of which gives black fur and another of which gives white fur.If you cross a black-colored female with a white-colored male,what would their male and female offspring look like?

Question 45

Describe a situation in which two aneuploid gametes would yield a euploid zygote.