Question 1

Which of the following best explains why sexual reproduction leads to greater genetic variation in offspring compared to asexual reproduction?

Accepted Answer

Sexual reproduction involves the fusion of gametes from two parents, allowing for independent assortment, crossing over, and random fertilization.

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 by exchanging DNA between non-sister chromatids.

Question 3

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

Accepted Answer

$$n = 4$$

Question 4

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

Accepted Answer

Independent assortment during Metaphase I

Question 5

A strawberry plant produces new plants via runners (stolons). What type of reproduction is this, and what is a major disadvantage?

Accepted Answer

Asexual reproduction; offspring are genetically identical, making them vulnerable to environmental changes.

Question 6

Which of the following equations correctly represents the number of possible chromosome combinations due to independent assortment in humans?

Accepted Answer

$$2^{23}$$

Question 7

What is the result of nondisjunction during meiosis, and which human disorder is caused by an extra copy of chromosome 21?

Accepted Answer

Aneuploidy; Down syndrome

Question 8

Which of the following best describes the difference between Meiosis I and Meiosis II?

Accepted Answer

Meiosis I separates homologous chromosomes; Meiosis II separates sister chromatids.

Question 9

A human zygote contains 46 chromosomes. Which process restores this diploid number after gamete formation?

Accepted Answer

Fertilization

Question 10

Which of the following events does NOT occur during Prophase I of meiosis?

Accepted Answer

Sister chromatids separate

Question 11

Why are siblings (except identical twins) genetically unique?

Accepted Answer

Because of independent assortment, crossing over, and random fertilization

Question 12

Which structure holds homologous chromosomes together during synapsis in Prophase I?

Accepted Answer

Synaptonemal complex

Question 13

If an organism has a haploid number of $$n = 5$$, how many genetically different gametes can it produce due to independent assortment alone?

Accepted Answer

$$2^5 = 32$

Question 14

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

Accepted Answer

Recombinant chromatids with new allele combinations

Question 15

Aphids can reproduce both sexually and asexually. What is the evolutionary advantage of this flexibility?

Accepted Answer

It allows survival in changing environments while maintaining genetic diversity.

Question 16

During which stage of meiosis do homologous chromosomes align at the metaphase plate, and what is the significance of their orientation?

Accepted Answer

Metaphase I; their random orientation leads to independent assortment.

Question 17

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

Accepted Answer

Four genetically unique haploid gametes are produced from one diploid cell.

Question 18

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

Accepted Answer

Binary fission

Question 19

If nondisjunction occurs during Meiosis II, what is the likely chromosomal composition of the resulting gametes?

Accepted Answer

Two normal gametes, one with an extra chromosome, and one missing a chromosome

Question 20

Which of the following statements about mitosis and meiosis is correct?

Accepted Answer

Mitosis produces genetically identical cells, while meiosis produces genetically unique gametes.

Meiosis and Sexual Reproduction: Study Notes for General Biology

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