Deck 3: Advanced Gene Mapping in Eukaryotes

Question 1

Male butterflies are the ________ sex.

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

Answer 1

E

Question 2

Chromosomes consist of

A) DNA and phospholipid.
B) DNA and protein.
C) DNA.
D) DNA and RNA.
E) all of the above.

Answer 2

B

Question 3

Gametes and spores are both haploid cells. Gametes form by ________ and spores form by ________.

A) meiosis, meiosis
B) mitosis, meiosis
C) meiosis, mitosis
D) A and B
E) A, B, and C

Answer 3

B

Question 4

Cells obtained from a normal woman would contain ________ Barr bodies.

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

Question 5

The chromosome theory of inheritance states that

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

Question 6

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

A) 1, 21
B) 1, 22
C) 1, Y
D) X, 22
E) none of the above

Question 7

Which of the following has heterogametic females?

A) house mice
B) monarch butterflies
C) crows
D) A, B, and C
E) B and C only

Question 8

In human males, genes on the X chromosome are

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

Question 9

The key gene in mammalian sex determination is

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

Question 10

Which of the following is an example of a genetic mosaic?

A) Calico coat color in cats
B) Albinism in mice
C) Red-green color blindness in humans
D) Male pattern baldness in humans
E) A, B, and C only

Question 11

In the insect order Hymenoptera, which includes ants, bees, and wasps, sex determination is based on

A) temperature.
B) a sex-determination locus.
C) the Y chromosome.
D) ploidy.
E) none of the above.

Question 12

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

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

Question 13

Which of the following organisms have environmental sex determination?

A) Snapping turtles
B) Butterflies
C) Roundworms
D) Birds
E) Kangaroos

Question 14

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

A) solid-colored female kittens.
B) calico male kittens.
C) calico female kittens.
D) solid-colored male kittens.
E) All of the above are possible.

Question 15

The chromosome theory of inheritance was proposed independently by

A) Sutton and Boveri.
B) Bateson and Morgan.
C) Hershey and Chase.
D) Watson and Crick.
E) Mendel and Correns.

Question 16

Turner syndrome individuals are

A) polyploidy.
B) aneuploid
C) haploid.
D) euploid.
E) none of the above.

Question 17

Which of the following statements is not true?

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

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

Question 19

Turner syndrome individuals are aneuploid because they

A) have an additional third set of all chromosomes.
B) lack a Y chromosome.
C) lack a Y chromosome and have an extra X chromosome.
D) have an extra Y chromosome.
E) have an extra copy of chromosome 21.

Question 20

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

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

Question 21

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 22

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

Question 23

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

Question 24

Y-linked traits are termed holandric.

Question 25

The X chromosome inherited from the father is always inactivated.

Question 26

How do you think chromosomes got their name?

Question 27

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 28

What is the connection between Mary Lyon and Murray Barr?

Question 29

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

Question 30

Describe two dosage compensation mechanisms found in animals.

Question 31

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

Question 32

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

Question 33

Nondisjunction leads to polyploidy.

Question 34

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

Question 35

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

Question 36

A person with two X chromosomes is the homogametic sex.

Question 37

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 38

Describe a situation where two aneuploid gametes would yield a eupoid zygote.

Question 39

Barr bodies are inactivated X chromosomes.

Question 40

Sea turtle sex determination is temperature dependent. What effect might global warming have on sea turtle sex ratios? What behavioral compensation might evolve in sea turtles to restore a balanced ratio?

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

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

Question 43

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 44

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