Question 1

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

Accepted Answer

Because meiosis involves crossing over and independent assortment, creating new combinations of alleles.

Question 2

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

Accepted Answer

Crossing over occurs during prophase I and increases genetic variation among gametes.

Question 3

A human cell with 46 chromosomes undergoes meiosis. How many chromosomes will each resulting gamete contain?

Accepted Answer

$$23$$

Question 4

Which of the following events during meiosis is responsible for independent assortment of chromosomes?

Accepted Answer

Alignment of homologous pairs at the metaphase plate during metaphase I.

Question 5

If nondisjunction occurs during meiosis II, what is the expected outcome for the resulting gametes?

Accepted Answer

Two gametes will be normal ($$n$$), one will have an extra chromosome ($$n+1$$), and one will be missing a chromosome ($$n-1).$$

Question 6

Which of the following best describes a bivalent during meiosis?

Accepted Answer

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

Question 7

What is the ploidy of a zygote formed by the fusion of two human gametes?

Accepted Answer

Diploid ($$2n)$$

Question 8

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

Accepted Answer

Formation of recombinant chromosomes with new allele combinations.

Question 9

A plant species has a diploid number of $$2n = 12. $$After meiosis, how many chromosomes will each gamete contain?

Accepted Answer

$$6$$

Question 10

Which of the following statements about polyploidy is correct?

Accepted Answer

Polyploidy refers to cells with more than two sets of chromosomes.

Question 11

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

Accepted Answer

Replication of DNA during S phase.

Question 12

A karyotype is useful for which of the following purposes?

Accepted Answer

Visualizing the number and structure of chromosomes in a cell.

Question 13

Which of the following best describes the difference between autosomes and sex chromosomes?

Accepted Answer

Autosomes are chromosomes other than sex chromosomes, and both types are inherited from both parents.

Question 14

Which of the following scenarios would most likely result in Down syndrome (trisomy 21) in a human offspring?

Accepted Answer

A gamete with $$n+1$$ chromosomes (an extra chromosome 21) is fertilized.

Question 15

Which of the following is a key difference between mitosis and meiosis?

Accepted Answer

Meiosis involves two rounds of cell division and results in haploid cells, while mitosis involves one round and results in diploid cells.

Question 16

If a primary oocyte in a human female fails to complete meiosis I properly, what is the most likely chromosomal outcome in the resulting egg?

Accepted Answer

The egg may have either $$n+1 or$$ $$n-1$$ chromosomes due to nondisjunction.

Question 17

Which of the following terms describes the physical location of a gene on a chromosome?

Accepted Answer

Locus

Question 18

Which of the following best explains why genetic recombination is important for evolution?

Accepted Answer

It creates new combinations of alleles that may provide a selective advantage in changing environments.

Question 19

Which of the following is true regarding the products of meiosis in animals?

Accepted Answer

Each product is haploid and genetically unique.

Chapter 13: Meiosis – Mechanisms and Significance

Study Guide - Practice Questions