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 different haploid cells.

Question 2

During which phase of the cell cycle does DNA replication occur, and what is the resulting number of chromatids per chromosome at the end of this phase in a human somatic cell?

Accepted Answer

DNA replication occurs during S phase, resulting in two chromatids per chromosome.

Question 3

Which protein complex is responsible for holding sister chromatids together, and what is its fate during the transition from metaphase to anaphase in mitosis?

Accepted Answer

Cohesin; it is degraded by separase, allowing sister chromatids to separate.

Question 4

A mutation prevents the formation of the synaptonemal complex during meiosis. Which process would be most directly affected?

Accepted Answer

Crossing over between homologous chromosomes during prophase I.

Question 5

Which of the following equations correctly represents the DNA content (in arbitrary units) of a human cell at the end of S phase, assuming the G1 phase DNA content is $$x$$?

Accepted Answer

$$2x$$

Question 6

In a cell with a diploid number of 8 chromosomes ($$2n = 8$$), how many chromosomes and chromatids are present in each daughter cell immediately after mitosis?

Accepted Answer

8 chromosomes and 8 chromatids

Question 7

Which checkpoint in the cell cycle ensures that all chromosomes are properly attached to the mitotic spindle before proceeding to anaphase?

Accepted Answer

Metaphase checkpoint

Question 8

A geneticist observes that a certain mutation causes homologous chromosomes to fail to separate during meiosis I. What is the most likely consequence for the resulting gametes?

Accepted Answer

Some gametes will have an extra chromosome, and some will be missing a chromosome (nondisjunction).

Question 9

Which of the following best explains why crossing over during meiosis increases genetic diversity?

Accepted Answer

It results in the exchange of genetic material between nonsister chromatids of homologous chromosomes.

Question 10

In human males, how do the X and Y chromosomes pair during meiosis I despite having few genes in common?

Accepted Answer

They pair through their pseudoautosomal regions (PARs).

Question 11

Which of the following events occurs during anaphase A of mitosis?

Accepted Answer

Kinetochore microtubules depolymerize, moving chromatids toward the centrioles.

Question 12

A cell is observed with chromosomes aligned at the metaphase plate, each chromosome consisting of two sister chromatids. Which phase is this cell in?

Accepted Answer

Metaphase

Question 13

Which of the following best describes the role of kinetochore microtubules during mitosis?

Accepted Answer

They attach to kinetochores on chromosomes and help segregate sister chromatids.

Question 14

If a mutation caused the cohesin protein to be nonfunctional, what would be the most likely effect during mitosis?

Accepted Answer

Sister chromatids would separate prematurely, leading to chromosome missegregation.

Question 15

Which of the following is a key event that distinguishes metaphase I of meiosis from metaphase of mitosis?

Accepted Answer

Homologous chromosomes align as tetrads on the metaphase plate in meiosis I.

Question 16

Which equation best represents the number of possible combinations of chromosomes in gametes due to independent assortment, where $$n is $$the haploid number?

Accepted Answer

$$2^n$$

Question 17

A researcher observes a cell with a contractile ring and cleavage furrow forming. Which process is most likely occurring?

Accepted Answer

Cytokinesis in an animal cell

Question 18

Which of the following best explains why mitosis is essential for multicellular organisms?

Accepted Answer

It generates genetically identical cells for growth and tissue repair.

Question 19

Which stage of prophase I in meiosis is characterized by the formation of chiasmata and the completion of crossing over?

Accepted Answer

Diplotene

Cell Division and Chromosome Heredity: Mitosis and Meiosis

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