Question 1

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

Accepted Answer

It produces four haploid (n) gametes, each genetically distinct from the parent cell and from each other.

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

If a fruit fly has a diploid number of 8 (2n = 8), how many different combinations of chromosomes are possible in its gametes due to independent assortment alone?

Accepted Answer

$$2^4 = 16$

Question 4

Which of the following events distinguishes meiosis I from meiosis II?

Accepted Answer

Separation of homologous chromosomes

Question 5

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

Accepted Answer

23 chromosomes

Question 6

Which of the following best explains why sexual reproduction results in greater genetic diversity than asexual reproduction?

Accepted Answer

Sexual reproduction involves independent assortment, crossing over, and random fertilization.

Question 7

What is the result if non-disjunction occurs during Anaphase I of meiosis?

Accepted Answer

Some gametes will have an extra chromosome (n+1) and some will have one less (n-1).

Question 8

Which of the following is a correct description of homologous chromosomes?

Accepted Answer

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

Question 9

A woman’s risk of producing an egg with an incorrect number of chromosomes increases with age. What is the most likely biological explanation for this?

Accepted Answer

Primary oocytes are arrested in Prophase I for many years, increasing the chance of errors in chromosome separation.

Question 10

Which of the following equations correctly represents the restoration of chromosome number during fertilization?

Accepted Answer

$$n + n = 2n$$

Question 11

Which process is responsible for the formation of recombinant chromosomes?

Accepted Answer

Crossing over during Prophase I

Question 12

If a mistake occurs during meiosis II such that sister chromatids fail to separate, what is the likely result?

Accepted Answer

Half the gametes will be normal, and half will be aneuploid (n+1 or n-1).

Question 13

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

Accepted Answer

Autosomes are chromosomes other than sex chromosomes; sex chromosomes are involved in determining an individual's sex.

Question 14

Which of the following statements about genetic recombination is correct?

Accepted Answer

Genetic recombination results from both independent assortment and crossing over during meiosis.

Question 15

A cell with genotype AaBb undergoes meiosis. Assuming independent assortment and no crossing over, what is the expected ratio of gamete genotypes?

Accepted Answer

1 AB : 1 Ab : 1 aB : 1 ab

Question 16

Which of the following is a likely consequence of aneuploidy in humans?

Accepted Answer

Most aneuploid zygotes result in miscarriage, but some can lead to developmental disorders such as Down syndrome.

Question 17

Which of the following best explains why offspring produced by self-fertilization (selfing) are more genetically diverse than those produced by asexual reproduction?

Accepted Answer

Self-fertilization allows for independent assortment and crossing over, increasing genetic diversity.

Question 18

During which stage of meiosis do homologous chromosomes line up at the metaphase plate?

Accepted Answer

Metaphase I

Question 19

Which of the following is true regarding the ploidy of cells during the animal life cycle?

Accepted Answer

Gametes are haploid (n), and zygotes are diploid (2n).

BIO 1113 Ch 13 part 1

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