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, creating haploid gametes

Question 2

During which phase of meiosis does crossing over occur, and what is its significance?

Accepted Answer

Prophase I; it increases genetic variation by exchanging DNA between homologous chromosomes

Question 3

If a diploid cell with 2n = 46 chromosomes undergoes meiosis, how many chromosomes will each resulting gamete contain?

Accepted Answer

$$23$$

Question 4

Which event during meiosis is responsible for the independent assortment of genes?

Accepted Answer

Alignment of homologous chromosomes at the metaphase I plate

Question 5

A cell in metaphase I of meiosis contains 10 chromosomes. How many chromosomes will each daughter cell have after telophase I?

Accepted Answer

$$5$$

Question 6

Which of the following statements correctly compares mitosis and meiosis?

Accepted Answer

Mitosis produces diploid cells, while meiosis produces haploid cells

Question 7

What is the genetic consequence of nondisjunction during meiosis?

Accepted Answer

Some gametes may have an extra or missing chromosome, leading to disorders such as Down syndrome

Question 8

Which structure is responsible for holding homologous chromosomes together during crossing over?

Accepted Answer

Chiasmata

Question 9

In the alternation of generations in plants, which stage is diploid?

Accepted Answer

Sporophyte

Question 10

A mutation causes a cell to skip crossing over during prophase I. What is the most likely consequence?

Accepted Answer

Gametes will have reduced genetic variation

Question 11

Which of the following best describes homologous chromosomes?

Accepted Answer

They carry genes for the same traits, but may have different alleles

Question 12

During which phase of meiosis do sister chromatids finally separate?

Accepted Answer

Anaphase II

Question 13

If a human cell at the start of meiosis I contains 46 chromosomes, how many DNA molecules are present after the completion of meiosis II?

Accepted Answer

$$23$$

Question 14

Which process restores the diploid number of chromosomes in sexually reproducing organisms?

Accepted Answer

Fertilization

Question 15

A geneticist observes a cell with chromosomes aligned in pairs at the metaphase plate. Which phase is this cell in?

Accepted Answer

Metaphase I

Question 16

Which of the following equations correctly represents the chromosome number in a zygote formed by the fusion of two human gametes?

Accepted Answer

$$n + n = 2n$$

Question 17

Which of the following is NOT a source of genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA during interphase

Question 18

A cell undergoes meiosis but fails to separate homologous chromosomes during anaphase I. What is the result?

Accepted Answer

Some gametes will have an extra chromosome, and some will be missing one

Question 19

Which phase of meiosis is most similar to mitosis, and why?

Accepted Answer

Meiosis II, because sister chromatids are separated

Question 20

Which of the following best explains why offspring produced by sexual reproduction are genetically unique?

Accepted Answer

They inherit a unique combination of genes due to crossing over, independent assortment, and random fertilization

Meiosis: Mechanisms and Genetic Variation

Study Guide - Practice Questions