Question 1

Which of the following best describes the main purpose of meiosis in sexually reproducing organisms?

Accepted Answer

To reduce the chromosome number by half and increase genetic variation in gametes

Question 2

During which specific phase of meiosis does crossing over (homologous recombination) occur?

Accepted Answer

Prophase I

Question 3

A cell with 2n = 6 undergoes meiosis. How many chromosomes will each gamete contain after meiosis is complete?

Accepted Answer

$$n = 3$$

Question 4

What is the key difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes are inherited from different parents, while sister chromatids are identical copies formed after DNA replication

Question 5

Which of the following events occurs in meiosis I but not in mitosis?

Accepted Answer

Pairing and separation of homologous chromosomes

Question 6

If a mistake occurs during meiosis I such that both homologous chromosomes go to the same daughter cell, what is the likely result after fertilization?

Accepted Answer

A zygote with an extra or missing chromosome (aneuploidy)

Question 7

Which of the following best explains why meiosis is necessary for sexual reproduction?

Accepted Answer

It maintains a constant chromosome number across generations

Question 8

During which stage of meiosis do homologous chromosomes line up side-by-side at the metaphase plate?

Accepted Answer

Metaphase I

Question 9

After DNA replication but before meiotic cell division, how many copies of each gene are present in a diploid cell?

Accepted Answer

Four copies

Question 10

Which of the following is a direct consequence of crossing over during meiosis?

Accepted Answer

Increased genetic variation among gametes

Question 11

A cell is observed with chromosomes aligned in pairs along the center of the cell. Which stage is this, and what is the ploidy of the cell at this point?

Accepted Answer

Metaphase I of meiosis; diploid

Question 12

Which of the following statements about aneuploidy is correct?

Accepted Answer

It can result from nondisjunction during either meiosis I or meiosis II

Question 13

Which process restores the diploid chromosome number after it has been halved during meiosis?

Accepted Answer

Fertilization

Question 14

In a human cell, how many chromosomes are present in a gamete after meiosis?

Accepted Answer

$$n = 23$$

Question 15

Which of the following mechanisms does NOT contribute to genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA without recombination

Question 16

A diploid cell with 8 chromosomes undergoes meiosis. How many different combinations of chromosomes are possible in the gametes due to independent assortment alone? (Assume no crossing over.)

Accepted Answer

$$2^4 = 16$

Question 17

Which of the following best describes the relationship between chromosome number and DNA content as a cell proceeds through meiosis?

Accepted Answer

Chromosome number is halved after meiosis I, and DNA content is halved after meiosis II

Question 18

Which of the following is true about the products of meiosis and mitosis?

Accepted Answer

Meiosis produces four genetically unique haploid cells, while mitosis produces two genetically identical diploid cells

Question 19

A cell is observed with chromosomes lined up single file at the metaphase plate, not in pairs. Which process and stage is this?

Accepted Answer

Metaphase of mitosis

Question 20

Which of the following is a consequence of errors in meiosis for human health?

Accepted Answer

Birth defects such as Down syndrome due to an extra chromosome

Meiosis: Mechanisms, Phases, and Biological Significance

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