1) A woman who is a carrier for the hemophilia gene has a child with a man who does not have hemophilia. Which prediction is correct?

A) All of the sons and none of the daughters will have hemophilia.

B) All of the daughters and none of the sons will have hemophilia.

C) Half of the sons and half of the daughters will have hemophilia.

D) Half of the sons and none of the daughters will have hemophilia.

E) Half of the daughters and none of the sons will have hemophilia.

2) A woman who does not carry the color-blindness allele has children with a man who is color blind. What proportion of their children will be color blind?

A) all

B) 1/4

C) 1/2

D) 3/4

E) none

3) Regarding the human sex chromosomes, which statement is correct?

A) The Y chromosome carries a greater number of genes than does the X chromosome.

B) X and Y are different in size but carry nearly equal numbers of genes.

C) The X chromosome carries more genes than does the Y chromosome.

D) The X chromosome carries only gender-related genes.

E) The X chromosome carries the genes for the development of male phenotype.

4) What percent of males have some degree of color blindness?

A) 0.5 percent

B) 5 percent

C) 0.8 percent

D) 8 percent

E) 10 percent

5) A trait such as albinism is seen with equal frequency in males and females. Two people who do not have the trait might have offspring who do have the trait, at a frequency of approximately one in four. What can you conclude about the inheritance of this trait?

A) recessive, X-linked

B) recessive, autosomal

C) recessive, caused by polyploidy

D) dominant, X-linked

E) dominant, autosomal

6) What is a recessive disorder?

A) a genetic disorder with two functioning alleles

B) a genetic disorder that will express itself in the presence of one functioning allele

C) a genetic disorder that will express itself in the presence of two recessive alleles

D) a genetic disorder that involves change in chromosome number

E) a genetic disorder that involves change in chromosome structure

7) Why do X-linked conditions appear more frequently in males than in females?

A) A male with a nonfunctioning allele on the X chromosome does not have another allele of that gene on the Y chromosome that could cover up the nonfunctioning one.

B) Males have no X chromosomes.

C) The Y chromosome carries many alleles that are recessive to alleles on the X chromosome.

D) Males are more likely to inherit an extra chromosome than females.

E) Females have no X chromosomes.

8) What do hemophilia, Duchenne muscular dystrophy, and red-green color blindness have in common?

A) They are X-linked.

B) They are more common in females than in males.

C) They are caused by inheritance of an extra sex chromosome.

D) They are caused by inheritance of an extra autosome.

E) The gene that causes them is on the Y chromosome.

9) If a daughter expresses an X-linked recessive gene, she probably inherited the trait from:

A) her mother.

B) her father.

C) both parents.

D) neither parent.

E) her grandmother.

10) Red-green color blindness is an X-linked recessive trait in humans. A color-blind woman and a man with normal vision have a son. What is the probability that the son is color blind?

A) 100 percent

B) 75 percent

C) 50 percent

D) 25 percent

E) 0 percent