Question 1

Which of the following best describes the main difference between the products of mitosis and meiosis in animal cells?

Accepted Answer

Mitosis produces two genetically identical diploid cells, while meiosis produces four genetically distinct haploid cells.

Question 2

During which stage of meiosis does crossing over and recombination between homologous chromosomes primarily occur?

Accepted Answer

Prophase I

Question 3

A mutation in a gene controlling the G1/S checkpoint of the cell cycle could most directly result in which of the following?

Accepted Answer

Failure to replicate DNA before mitosis

Question 4

Which equation correctly represents the change in chromosome number during meiosis in a diploid organism with $$2n$$ chromosomes?

Accepted Answer

$$2n \rightarrow n$$

Question 5

The synaptonemal complex is essential for which of the following processes?

Accepted Answer

Alignment and recombination of homologous chromosomes during prophase I of meiosis

Question 6

A male Drosophila melanogaster with a white-eye mutation is crossed with a wild-type red-eyed female. All F1 offspring have red eyes. What does this indicate about the inheritance of the white-eye trait?

Accepted Answer

The white-eye allele is recessive and X-linked.

Question 7

Which of the following best explains why calico and tortoiseshell cats are almost always female?

Accepted Answer

Random X-chromosome inactivation in heterozygous females leads to mosaic expression of coat color alleles.

Question 8

Which of the following is a direct consequence of nondisjunction during meiosis?

Accepted Answer

Production of gametes with abnormal numbers of chromosomes

Question 9

In placental mammals, what is the role of the XIST gene in dosage compensation?

Accepted Answer

It produces RNA that coats and inactivates one X chromosome in female cells.

Question 10

Which of the following best describes the law of independent assortment as it relates to meiosis?

Accepted Answer

Homologous chromosomes separate randomly during anaphase I, leading to genetic variation in gametes.

Question 11

A human male with a mutation in the SRY gene would most likely exhibit which phenotype?

Accepted Answer

Female physical characteristics despite having an XY karyotype

Question 12

Which of the following is true regarding Y-linked inheritance in humans?

Accepted Answer

Y-linked traits are transmitted exclusively from father to son.

Question 13

In the Z/W sex determination system found in birds, which of the following is correct?

Accepted Answer

Females are ZW and males are ZZ.

Question 14

A woman who is heterozygous for an X-linked recessive disorder has children with a man who does not have the disorder. What is the probability that their son will have the disorder?

Accepted Answer

$$\frac{1}{2}$$

Question 15

Which of the following mechanisms is NOT a form of dosage compensation?

Accepted Answer

Nondisjunction of sex chromosomes during meiosis

Question 16

Which of the following best explains why female mammals are considered genetic mosaics?

Accepted Answer

Each cell randomly inactivates either the maternal or paternal X chromosome, leading to two populations of cells.

Question 17

If a cell fails to pass the metaphase checkpoint during mitosis, what is the most likely outcome?

Accepted Answer

The cell will not proceed to anaphase until all chromosomes are properly attached to the spindle apparatus.

Question 18

Which of the following is a hallmark of X-linked recessive inheritance in humans?

Accepted Answer

The trait is expressed much more often in males than in females.

Question 19

Which of the following best describes the function of the pseudoautosomal regions (PARs) on the X and Y chromosomes?

Accepted Answer

They allow pairing and recombination between X and Y chromosomes during male meiosis.

Cell Division and Chromosome Heredity: Mitosis, Meiosis, and Sex Chromosome Inheritance

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