Question 1

Which of the following best describes the main outcome of meiosis in animals?

Accepted Answer

It produces four haploid cells that are genetically distinct from each other and the parent cell.

Question 2

During which phase of meiosis do homologous chromosomes separate?

Accepted Answer

Anaphase I

Question 3

If a diploid organism has a haploid number $$n = 8$$, how many possible combinations of chromosomes can result from independent assortment during meiosis?

Accepted Answer

$$2^8 = 256$

Question 4

Which of the following events increases genetic variation during meiosis?

Accepted Answer

Crossing over between non-sister chromatids during prophase I

Question 5

A cell with three sets of chromosomes (3n) is best described as:

Accepted Answer

Polyploid

Question 6

What is the result if nondisjunction occurs during meiosis I in humans?

Accepted Answer

Half of the gametes will have an extra chromosome, and half will have one fewer chromosome.

Question 7

Which of the following best explains why sexual reproduction leads to greater genetic diversity than asexual reproduction?

Accepted Answer

Sexual reproduction involves the fusion of gametes and processes like crossing over and independent assortment.

Question 8

In humans, what is the diploid number of chromosomes, and how is it restored after meiosis?

Accepted Answer

2n = 46; restored by fertilization

Question 9

Which of the following is true about homologous chromosomes?

Accepted Answer

They carry the same genes in the same order but may have different alleles.

Question 10

A karyotype of a person with Down syndrome shows three copies of chromosome 21. This condition is an example of:

Accepted Answer

Trisomy

Question 11

Which of the following best describes a bivalent during meiosis?

Accepted Answer

A structure consisting of two homologous chromosomes, each with two sister chromatids, paired during prophase I

Question 12

If a human egg cell with an extra chromosome (n+1) is fertilized by a normal sperm (n), what will be the chromosome number of the resulting zygote?

Accepted Answer

$$2n + 1 = 47$$

Question 13

Which of the following statements about crossing over is correct?

Accepted Answer

It results in the exchange of genetic material between non-sister chromatids of homologous chromosomes.

Question 14

A fruit fly has a diploid number of 8 chromosomes. After meiosis, how many chromosomes will each gamete contain?

Accepted Answer

4

Question 15

Which of the following is a direct consequence of independent assortment during meiosis?

Accepted Answer

Each gamete receives a random mix of maternal and paternal chromosomes.

Question 16

What is the ploidy of a cell immediately after meiosis I in humans?

Accepted Answer

Haploid (n), with replicated chromosomes

Question 17

Which of the following best explains why the frequency of Down syndrome increases with the age of the egg-producing parent?

Accepted Answer

Older eggs are more likely to undergo nondisjunction during meiosis I.

Question 18

Which of the following is NOT a difference between mitosis and meiosis?

Accepted Answer

Mitosis involves synapsis of homologous chromosomes, while meiosis does not.

Question 19

If a plant species is tetraploid (4n = 48), what is its haploid number?

Accepted Answer

24

Question 20

Which of the following best describes aneuploidy?

Accepted Answer

A condition in which a cell has an abnormal number of chromosomes, such as trisomy or monosomy.

Chapter 13: Meiosis – Mechanisms and Significance in Genetic Variation

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