Question 1

Which of the following best explains why offspring produced by sexual reproduction are genetically different from their parents?

Accepted Answer

Because meiosis introduces genetic variation through crossing-over, independent assortment, and random fertilization.

Question 2

In humans, what is the value of $$n in $$the haploid number of chromosomes?

Accepted Answer

$$n = 23$$

Question 3

Which process during meiosis is primarily responsible for generating new combinations of alleles on the same chromosome?

Accepted Answer

Crossing-over during prophase I

Question 4

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

Accepted Answer

4

Question 5

Which of the following events does NOT occur during interkinesis?

Accepted Answer

DNA replication

Question 6

A human cell with 47 chromosomes is most likely the result of which meiotic error?

Accepted Answer

Nondisjunction

Question 7

Which of the following best describes the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes are inherited from each parent; sister chromatids are the result of DNA replication.

Question 8

Which stage of meiosis is responsible for reducing the chromosome number from diploid to haploid?

Accepted Answer

Meiosis I

Question 9

If nondisjunction occurs during meiosis II, which of the following is a possible outcome for the gametes?

Accepted Answer

Half the gametes will be normal, one will have an extra chromosome, and one will be missing a chromosome.

Question 10

Why is the unequal division of cytoplasm during oogenesis important?

Accepted Answer

It provides one egg with sufficient nutrients and organelles for early development.

Question 11

Which of the following mechanisms does NOT contribute to genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA during S phase

Question 12

A plant species has a diploid number of 12 chromosomes. After meiosis, how many different combinations of chromosomes are possible in its gametes due to independent assortment alone?

Accepted Answer

$$2^{6} = 64$

Question 13

Which of the following is true about polyploidy?

Accepted Answer

It results in individuals with three or more sets of chromosomes.

Question 14

What would happen if meiosis did NOT reduce the chromosome number in gametes?

Accepted Answer

The chromosome number would double with each generation.

Question 15

Which of the following best describes the outcome of spermatogenesis in humans?

Accepted Answer

Four haploid sperm

Question 16

A karyotype of a human cell shows 47 chromosomes, including three copies of chromosome 21. This condition is known as:

Accepted Answer

Trisomy 21 (Down syndrome)

Question 17

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry the same genes but may have different alleles.

Question 18

Which of the following is a direct result of primary nondisjunction during meiosis I?

Accepted Answer

Half the gametes have an extra chromosome, and half are missing a chromosome.

Question 19

Which of the following best explains why most miscarriages are caused by aneuploidy?

Accepted Answer

Aneuploidy results in a lethal imbalance of genetic material.

Question 20

During which phase of meiosis does independent assortment of chromosomes occur?

Accepted Answer

Metaphase I

Meiosis and Sexual Reproduction: Mechanisms, Consequences, and Genetic Variation

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