Mac 5: End

Question 1

In Drosophila flies, eye color is a sex-linked. The allele for red eyes (XW) is dominant to the allele for white eyes (XW). A male fly with red eyes XWY and a carrier female (XWxW) are mated. What is the probability that the female offspring will have white eyes?

• 50%
• 100%
• 25%
• 0%

Answer 1

-0%

Question 2

Which Statement is/are true or false?

Females must inherit recessive X-linked alleles from both of their parents in order to express the trait.

When they inherit one recessive X-linked mutant allele and one dominant X-linked wild-type allele, they are carriers of the trait and are typically unaffected.

Answer 2

-Both statements are True

Question 3

In a cross between a white-eyed female fruit fly and red-eyed male, what percent of the female offspring will have white-eyes? (White eyes are X-linked, recessive)

• 50%
• 100%
• 25%
• 0%

Answer 3

-0%

Question 4

Hemophilia (h) is recessive x-linked disorder. Which genotype represents a male with hemophilia?

• XhY
• XHY
• XHyh
• XhXh

Answer 4

-XhY

Question 5

Male-pattern baldness is X-linked recessive trait, labelled Xb, with the dominant normal hair gene being XB. A father with genotype XBY and a mother with the genotype XbXb have a son.
What is the percent chance that the son will inherit male-pattern baldness?

• 0
• 75
• 25
• 100

Answer 5

-100

Question 6

Men with red-green color blindness inherited the genes for it from

• Their mothers
• None of the Above
• Their fathers
• Either their mothers or fathers

Answer 6

-Their mothers

Question 7

Male body cells only have one X chromosome, while females have two chromosomes. It is hypothesized that if both X chromosomes of a female were activated and functioning, they could cause metabolic dysfunction. Which of the following helps prevent this from occurring?

• The second X-chromosomes is converted into a smaller Y chromosomes
• Barr bodies are used to dissolve the extra x chromosome so that only one X remains
• X-inactive “switched off” one of the X chromosomes
• Each X chromosome takes a turn being active in a cell

Answer 7

-X-inactive “switched off” one of the X chromosomes

Question 8

A gene called___ in part of the X chromosomes called the X inactivation center controls X-inactivation.

• XIST
• SIXT
• XXT
• SZIST

Answer 8

-XIST

Question 9

Color blindness is a sex-linked recessive trait in humans. A woman who is a carrier for color blindness has children with a man who is color blind. Which of the following is true regarding their offspring?

• No daughters are color blind
• Any daughter is either color blind or a carrier
• All sons are color blind
• All sons are carriers

Answer 9

-Any daughter is either color blind or a carrier

Question 10

Which Statement is/are true or false?

An X-linked Dominant Trait is expressed in females in one copy.

It has more severe effects in females.

Answer 10

-First statement is True, Second statement is False (more severe in male)

Question 11

Hemophilia (h) is a recessive x-linked disorder. Which genotype represents a female who is a carrier for hemophilia?

• XHXh
• XHXH
• XhY
• XhXh

Answer 11

-XHXh

Question 12

Red-green color blindness is

• An X-linked trait
• An Y-linked trait
• All of the choices
• Both X and Y linked

Answer 12

-An X-linked trait

Question 13

Heterozygous individuals that can pass on recessive, abnormal conditions even if they do not express the disease are referred to as ____

• Zygote
• Deleterious donators
• Recessively compromised
• Phenotypically challenge
• Carriers

Answer 13

-Carriers

Question 14

Which of the following pairs of parents is most likely to produce a daughter with hemophilia?

• A carrier mother and an unaffected father
• A carrier mother and a hemophiliac father
• A hemophiliac mother and an unaffected father
• An unaffected, non-carrier mother and a hemophiliac father.

Answer 14

-A carrier mother and a hemophiliac father

Question 15

Which Statement is/are true or false?

Human males and females have equal numbers of autosomes.

Males have one X chromosome and one Y chromosome, and females have two X-chromosomes.

Answer 15

-Both statements are true

Question 16

Hemophilia A (h) is a recessive x-linked disorder. Which genotype represents a female with hemophilia?

• XhY
• XhXh
• XHXH
• XHXh

Answer 16

-XhXh

Question 17

A chicken with the sex chromosomes ZW is female, and ZZ is male. Which gamete determines the offsprings sex and why?

• The female, because of the W chromosome
• The female, because of the Z chromosome
• The male, because of the W chromosome
• The male, because of the Z chromosome

Answer 17

-The female, because of the W chromosome

Question 18

Which among following is true about sex chromosomes in humans?

• They only carry information for maleness and femaleness
• Y chromosomes carry more genes than X chromosomes
• They carry genes that have nothing to do with biological gender.
• Females have two X chromosomes and males have an X and a Y chromosomes.

Answer 18

-Females have two X chromosomes and males have an X and a Y chromosomes.

Question 19

Hemophilia is an X-linked recessive condition in which blood does not clot properly, Queen Victoria of England had one allele for hemophilia. Most of her male descendants had the disorder, but few females had it. Why did hemophilia occur more frequently in Queen Victoria’s male descendants?

• Males mature more slowly than females, allowing recessive traits more time to appear.
• Replication of the X chromosome occurs often in males but rarely in females.
• Only one copy of the X-chromosome is found in cells of males, but two copies are found in cells of females.
• Males have hormones that enhance the expression of X-linked traits.

Answer 19

-Only one copy of the X-chromosome is found in cells of males, but two copies are found in cells of females.

Question 20

Y-linked traits are inherited

• Only by females
• Only by males
• Both males and females
• Neither females or males

Answer 20

-Only by males