BIOLOGY 151 – A male child is born with an XYY constitution

10 Jun BIOLOGY 151 – A male child is born with an XYY constitution

Question
1) A male child is born with an XYY constitution of sex chromosomes. The parents are normal XX and XYindividuals, so their child’s genotype must be the result of nondisjunction (failure of chromosomes to separate during division) in the formation of one of their gametes. When (and in whom) could the nondisjunction have taken place?

Select one:

a. in the zygote at the first mitotic division

b. in the father in meiosis II

c. in the father in meiosis I

d. in the father in mitosis

e. in the mother in meiosis I

2) What is the probability that an individual is Aa or AA if his or her parents are both heterozygous for the trait?

Select one:

a. ¼

b. 1

c. ½

d. ¾

3) Mendel’s principle of independent assortment corresponds to which part of meiosis?

Select one:

a. random alignment of homologs on the metaphase plate during metaphase II

b. random pairing of homologs during prophase I

c. random alignment of homologs on the metaphase plate during metaphase I

d. separation of daughter chromatids during anaphase II

e. separation of chromosomes in anaphase I

4) In humans, ability to roll the tongue (R) is dominant to being unable to roll (r). Having freckles (F) is dominant to having no freckles (f). A man heterozygous for both traits marries a woman heterozygous for both traits. What is the probability that they will have a child with freckles?

Select one:

a. 1/4

b. 3/4

c. 1/16

d. 9/16

e. 3/16

5) For unlinked genes, the sorting of one gene pair influences the sorting of another gene pair.

Select one:

True

False

6) Segregation of alleles corresponds to the separation of:

Select one:

a. genotypes.

b. genes.

c. phenotypes.

d. chromosomes.

7) Animals that sexually reproduce are ________ and produce __________ gametes.

Select one:

a. diploid; diploid

b. haploid; diploid

c. haploid; haploid

d. diploid; haploid

8) You are studying two traits in fruit flies:

(1) eye color where there are two colors: brown and red.

(2) wing shape where there are straight and curled phenotypes.

You mate two flies that are heterozygous for the genes that control both of these traits and get the following phenotypes in the following ratio:

9 red and straight:3 red and curled:3 brown and straight:1 brown and curled

Considering these traits, which alleles separated at which stages of meiosis?

Select one:

a. Red segregated from straight in meiosis I, and brown segregated from curled in meiosis II.

b. Red segregated from brown in meiosis I, and straight segregated from curled in meiosis I.

c. Red segregated from brown in meiosis II, and straight segregated from curled in meiosis I.

d. Red segregated from brown in meiosis II, and straight segregated from curled in meiosis II.

e. Red segregated from brown in meiosis I, and straight segregated from curled in meiosis II.

9) In humans, ability to roll the tongue (R) is dominant to being unable to roll (r). Having freckles (F) is dominant to having no freckles (f). A freckled tongue-roller could have which of the following genotypes?

Select one:

a. RRFF

b. RrFf

c. rrFF

d. RRFFand RrFf only

e. All of these choices are correct.

10) You are examining a human pedigree for a trait. You notice that the trait appears in every generation; is equally likely to occur in males and females; and, when one parent is affected, about half of his or her offspring are affected. The trait is most likely:

Select one:

a. dominant.

b. recessive.

c. epistatic.

d. produced by multiple alleles.

e. one that shows incomplete penetrance.