Question 1

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

Accepted Answer

Meiosis reduces the chromosome number by half, preventing chromosome doubling in each generation.

Question 2

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

Accepted Answer

Prophase I; segments of DNA are exchanged between non-sister chromatids of homologous chromosomes.

Question 3

A diploid cell with $$2n = 24$$ chromosomes undergoes meiosis. How many chromosomes will each gamete have?

Accepted Answer

$$12$$

Question 4

Which event is unique to meiosis and directly increases genetic variation among offspring?

Accepted Answer

Crossing over during synapsis in Prophase I

Question 5

If a species has a haploid number $$n = 4$$, how many possible combinations of chromosomes can result from independent assortment alone?

Accepted Answer

$$2^4 = 16$

Question 6

Which of the following statements correctly describes the relationship between the cells at the end of meiosis II and the original cell?

Accepted Answer

The new cells have one copy of half of the genetic information in the original cell.

Question 7

Which of the following is a major difference between Anaphase I of meiosis and Anaphase of mitosis?

Accepted Answer

Homologous chromosomes separate in Anaphase I, while sister chromatids separate in mitosis.

Question 8

Which of the following best describes homologous chromosomes?

Accepted Answer

Chromosome pairs that carry genes for the same traits but may have different alleles.

Question 9

What would be the consequence if nondisjunction occurred during meiosis I?

Accepted Answer

Some gametes would have an extra chromosome, while others would have one less.

Question 10

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

Accepted Answer

DNA replication during S phase

Question 11

Which chromosomal abnormality is associated with Down syndrome?

Accepted Answer

Trisomy 21

Question 12

Which term describes the physical site where crossing over occurs between homologous chromosomes?

Accepted Answer

Chiasma

Question 13

A mutation causes crossing over to occur at twice the normal rate in a species. Which of the following is a likely consequence?

Accepted Answer

Increased genetic variation and higher risk of chromosomal structural abnormalities.

Question 14

Which of the following best describes the difference between mitosis and meiosis in terms of genetic diversity?

Accepted Answer

Meiosis produces genetically unique gametes, while mitosis produces identical somatic cells.

Question 15

Which of the following chromosomal changes is most likely to cause cancer, such as chronic myelogenous leukemia?

Accepted Answer

Reciprocal translocation

Question 16

Which of the following is true about gametes produced by meiosis?

Accepted Answer

They are haploid and genetically unique due to crossing over and independent assortment.

Question 17

Which of the following best describes the process of gametogenesis?

Accepted Answer

The process in which cells undergo meiosis to form gametes.

Question 18

Which of the following would NOT be observed during Prophase I of meiosis?

Accepted Answer

Separation of sister chromatids

Question 19

Which of the following is a correct formula for calculating the number of possible chromosome combinations in gametes due to independent assortment?

Accepted Answer

$$2^n$$, where $$n is $$the haploid number

Question 20

Which of the following is a real-world consequence of nondisjunction during meiosis?

Accepted Answer

Formation of gametes with abnormal chromosome numbers, leading to conditions such as Down syndrome or Turner syndrome.

Meiosis and Sexual Reproduction: Mechanisms, Genetic Variation, and Chromosomal Abnormalities

Study Guide - Practice Questions