Question 1

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

Accepted Answer

It 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 its significance?

Accepted Answer

Prophase I; it increases genetic variation among gametes.

Question 3

If a diploid cell with 2n = 8 undergoes meiosis, how many chromosomes will each resulting gamete contain?

Accepted Answer

$$4$$

Question 4

Which process is responsible for the random distribution of maternal and paternal chromosomes into gametes?

Accepted Answer

Independent assortment

Question 5

A karyotype reveals an individual with three copies of chromosome 21. What is the most likely diagnosis?

Accepted Answer

Down syndrome (Trisomy 21)

Question 6

Which of the following events occurs during Anaphase I of meiosis but NOT during Anaphase of mitosis?

Accepted Answer

Homologous chromosomes separate and move to opposite poles.

Question 7

What is the result of nondisjunction during meiosis?

Accepted Answer

Some gametes have an abnormal number of chromosomes, leading to aneuploidy.

Question 8

Which chromosomal mutation involves a segment of a chromosome being reversed end to end?

Accepted Answer

Inversion

Question 9

In human females, when does the process of oogenesis begin and end?

Accepted Answer

It begins before birth and ends at menopause.

Question 10

Which of the following best describes the difference between meiosis and mitosis?

Accepted Answer

Meiosis involves two nuclear divisions and results in haploid cells; mitosis involves one nuclear division and results in diploid cells.

Question 11

A species has a diploid number of 10 chromosomes. How many genetically different gametes can be produced by independent assortment alone?

Accepted Answer

$$2^5 = 32$

Question 12

Which syndrome is caused by the presence of a single X chromosome and no Y chromosome (XO)?

Accepted Answer

Turner syndrome

Question 13

Which of the following is a real-life example of a chromosomal translocation causing disease?

Accepted Answer

Chronic myelogenous leukemia

Question 14

What is the significance of genetic variation produced by meiosis in a changing environment?

Accepted Answer

It increases the likelihood that some offspring will survive environmental changes.

Question 15

Which of the following best describes the alternation of generations in plants?

Accepted Answer

Plants alternate between multicellular haploid and multicellular diploid individuals.

Question 16

A cell undergoes meiosis but a pair of homologous chromosomes fails to separate during Anaphase I. What is the result after fertilization?

Accepted Answer

Some resulting zygotes will be aneuploid, with either one extra or one missing chromosome.

Question 17

Which of the following statements about homologous chromosomes is TRUE?

Accepted Answer

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

Question 18

In which phase of meiosis do sister chromatids finally separate and move to opposite poles?

Accepted Answer

Anaphase II

Question 19

Which of the following is a direct consequence of a deletion mutation in a chromosome?

Accepted Answer

A segment of the chromosome is lost, possibly removing essential genes.

Question 20

Why are extra copies of sex chromosomes generally more tolerated than extra copies of autosomes in humans?

Accepted Answer

Sex chromosomes have mechanisms for dosage compensation, such as X-inactivation.

Meiosis and Sexual Reproduction: A Comprehensive Study Guide

Study Guide - Practice Questions