Question 1

Which of the following best explains why offspring resemble their parents but are not identical to them?

Accepted Answer

Offspring inherit genes from both parents, and genetic variation arises from mechanisms such as independent assortment and crossing over during meiosis.

Question 2

In humans, somatic cells contain 46 chromosomes. What is the chromosome number in a human gamete, and what term describes this condition?

Accepted Answer

23 chromosomes; haploid

Question 3

Which process is responsible for reducing the chromosome number from diploid to haploid in sexually reproducing organisms?

Accepted Answer

Meiosis

Question 4

A karyotype is used to examine chromosomes in a cell. Which of the following statements about karyotypes is correct?

Accepted Answer

A karyotype is an ordered display of all pairs of chromosomes from a cell, including autosomes and sex chromosomes.

Question 5

Which of the following equations correctly represents the diploid chromosome number in humans?

Accepted Answer

$$2n = 46$$

Question 6

During which phase of meiosis do homologous chromosomes separate, and what is the result?

Accepted Answer

Anaphase I; homologous chromosomes move to opposite poles, resulting in haploid cells with duplicated chromosomes

Question 7

Which mechanism contributes most directly to genetic variation among offspring in sexually reproducing organisms?

Accepted Answer

Crossing over during prophase I of meiosis

Question 8

If a plant species has a diploid number of 8 ($$2n = 8$$), how many possible combinations of chromosomes can result from independent assortment during meiosis?

Accepted Answer

$$2^4 = 16$

Question 9

Which of the following statements about the alternation of generations in plants is correct?

Accepted Answer

The haploid gametophyte produces gametes by mitosis.

Question 10

Which event is unique to meiosis and does NOT occur in mitosis?

Accepted Answer

Synapsis and crossing over between homologous chromosomes

Question 11

A mutation occurs in a gene that codes for a protein involved in DNA repair. Which of the following is a likely consequence for the organism?

Accepted Answer

The organism will have increased genetic variation due to more mutations.

Question 12

Which of the following best describes the outcome of meiosis II?

Accepted Answer

Sister chromatids are separated, resulting in four genetically distinct haploid cells.

Question 13

In a sexually reproducing animal, what is the significance of random fertilization?

Accepted Answer

It increases genetic variation by allowing any sperm to fuse with any egg, resulting in a zygote with a unique combination of chromosomes.

Question 14

Which of the following is true regarding the chromosome composition of a human zygote?

Accepted Answer

It contains one set of chromosomes from each parent, totaling 46 chromosomes.

Question 15

Which of the following mechanisms is responsible for the creation of recombinant chromosomes?

Accepted Answer

Crossing over during prophase I of meiosis

Question 16

A bdelloid rotifer is an animal that reproduces only asexually. Which statement best describes how it increases genetic diversity?

Accepted Answer

By incorporating foreign DNA from the environment

Question 17

Which of the following is a consequence of the independent assortment of chromosomes during meiosis?

Accepted Answer

Each gamete receives a random combination of maternal and paternal chromosomes.

Question 18

Which equation represents the number of possible chromosome combinations due to independent assortment in gametes, where $$n is $$the haploid number?

Accepted Answer

$$2^n$$

Question 19

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

Accepted Answer

Prophase I; it increases genetic variation by exchanging DNA between homologous chromosomes

Question 20

Which of the following best explains why sexual reproduction is nearly universal among animals?

Accepted Answer

It increases genetic variation, which is favored by natural selection and contributes to evolution.

Meiosis and Sexual Life Cycles: Study Guide for General Biology

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