Chapter 4 Flashcards
What is the role of the SRY gene in humans?
a. It initiates the X inactivation process in females.
b. It is located on the X chromosome and causes the X to pair with the Y chromosome during male meiosis.
c. It is located on the Y chromosome and initiates the developmental pathway toward the male phenotype.
d. It is located on an autosomal chromosome and represses expression of autosomal genes in order to balance their expression level with genes on the X chromosome.
e. None of the above answers is correct.
c. It is located on the Y chromosome and initiates the developmental pathway toward the male phenotype.
What is the expected outcome for a human embryo with the XXXY chromosome constitution?
a. It would likely develop into a female who will not respond to the hormone testosterone.
b. It would likely develop into a sterile male with reduced testes.
c. It will always abort early in development before birth.
d. It would likely develop into a tall female who may be slightly cognitively impaired.
e. It would likely develop into a fertile man with a completely normal male phenotype.
b. It would likely develop into a sterile male with reduced testes.
Which of the following chromosome constitutions would never lead to a viable human baby being born?
a. XXX
b. XYY
c. XO (O = the absence of a second chromosome)
d. YY
e. XXY
d. YY
A female with androgen-insensitivity syndrome, a sex-linked recessive condition, has
a. two X chromosomes, both carrying mutant alleles in the gene that makes the androgen receptor.
b. a pair of ovaries that overproduce estrogen.
c. a XXX chromosome constitution that causes her not to produce testosterone.
d. a pair of testes that produce testosterone.
e. an inactive SRY gene.
d. a pair of testes that produce testosterone.
Species in which individuals have only male or only female reproductive structures are called
a. hermaphrodites.
b. diploids.
c. dioecious.
d. homogametic.
e. monoecious.
c. dioecious.
In which of the following organisms is gender/sex determined by the temperature during embryonic development?
a. Humans
b. Mice
c. Fruit flies
d. Many snakes and birds
e. Many turtles and alligators
e. Many turtles and alligators
In species of birds, males are the homogametic sex and females the heterogametic sex. Which if the following is true in this system of sex determination?
a. The gender of the offspring is determined by the female parent.
b. Male offspring have a ZW chromosome constitution.
c. The gender of the offspring is determined by the male parent.
d. Female offspring have a ZZ chromosome constitution.
e. Female and male offspring have the same chromosome constitution.
a. The gender of the offspring is determined by the female parent.
In a germ-line cell from a female grasshopper (XX-XO sex determination system), when do the homologous X chromosomes segregate?
a. During mitosis
b. During meiosis I, anaphase
c. During meiosis II, anaphase
d. They do not segregate; gametes contain a copy of X and a copy of Y.
b. During meiosis I, anaphase
In a germ-line cell from a human male that is dividing, when do the X and Y chromosomes segregate?
a. During mitosis
b. During meiosis I, anaphase
c. During meiosis II, anaphase
d. They do not segregate; gametes contain a copy of X and a copy of Y.
b. During meiosis I, anaphase
Which of the following human genotypes is associated with Klinefelter syndrome?
a. XXY
b. XXXY
c. XXXXY
d. All of the above
e. None of the above
d. All of the above
What is the sex chromosome constitution of a male duck-billed platypus?
a. XX
b. XY
c. XO
d. ZZ
e. XXXXXYYYYY
e. XXXXXYYYYY
An XXY chromosome constitution produces ________ development in humans and _________ development in fruit flies.
a. female; female
b. male; male
c. female; male
d. male; female
e. male, intersex
d. male; female
The sex determination system used by Drosophila is called
a. the X:A sex determination system.
b. the ZZ-ZW sex determination system.
c. the XX-XO sex determination system.
d. the XX-XY sex determination system.
e. Both b and c are correct.
a. the X:A sex determination system.
With the XX-XO sex determination system, generally
a. female offspring have one X chromosome, and it is inherited from their father.
b. male offspring have one X chromosome, and it is inherited from their mother.
c. male offspring have one X chromosome, and it is inherited from their father.
d. female offspring have one X chromosome, and it is inherited from their mother.
e. None of the above statements is true.
b. male offspring have one X chromosome, and it is inherited from their mother.
Species in which an individual organism has both male and female reproductive structures are called
a. monoecious.
b. haploid.
c. diploid.
d. dioecious.
e. Both c and d are correct.
a. monoecious.
Human females with XY chromosomes and a phenotype that includes the absence of a uterus and ovaries and the presence of testes are likely to have which of the following mutations?
a. A mutation in the SRY gene
b. A mutation in the androgen receptor gene
c. A deletion that removes much of the Y chromosome
d. They likely do not carry a mutation but may have been premature babies.
e. None of the above answers is correct.
b. A mutation in the androgen receptor gene
Human males, with XY chromosomes are___________ and produce two different kinds of gametes, whereas females with XX chromosomes are ___________ and produce only one kind.
a. homogametic; heterogametic
b. dioecious; monoecious
c. heterogametic; homogametic
d. monoecious; dioecious
e. monoecious; heterogametic
c. heterogametic; homogametic