Question 1

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

Accepted Answer

Because meiosis and fertilization shuffle alleles, resulting in unique combinations of genes.

Question 2

A human somatic cell contains 46 chromosomes. How many chromosomes are present in a human gamete, and what is this condition called?

Accepted Answer

23 chromosomes; haploid

Question 3

Which of the following events occurs only during meiosis and not mitosis?

Accepted Answer

Synapsis and crossing over between homologous chromosomes

Question 4

If an organism has a diploid number of 8 ($$2n = 8$$), how many possible combinations of chromosomes could be produced in its gametes by independent assortment alone?

Accepted Answer

$$2^4 = 16$

Question 5

During which phase of meiosis do homologous chromosomes separate and move toward opposite poles?

Accepted Answer

Anaphase I

Question 6

Which of the following statements about crossing over is correct?

Accepted Answer

It produces recombinant chromosomes that combine DNA from both parents.

Question 7

A karyotype is useful for which of the following purposes?

Accepted Answer

Identifying the number and structure of chromosomes in a cell

Question 8

In plants exhibiting alternation of generations, which process directly produces haploid gametes?

Accepted Answer

Mitosis in the gametophyte

Question 9

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

Accepted Answer

Replication of DNA during S phase

Question 10

A mutation in a gene results in a new allele. What is the evolutionary significance of this event?

Accepted Answer

It is the original source of genetic diversity upon which natural selection can act.

Question 11

Which of the following best describes the difference between asexual and sexual reproduction?

Accepted Answer

Asexual reproduction produces genetically identical offspring, while sexual reproduction produces genetically diverse offspring.

Question 12

In humans, what is the result of meiosis in the testes?

Accepted Answer

Four haploid sperm cells

Question 13

Which of the following is true regarding the behavior of chromosomes during the human life cycle?

Accepted Answer

Fertilization restores the diploid number of chromosomes in the zygote.

Question 14

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

Accepted Answer

$$2^n$$

Question 15

A researcher observes a cell with homologous chromosomes aligned at the metaphase plate, each consisting of two sister chromatids. Which stage of meiosis is being observed?

Accepted Answer

Metaphase I

Question 16

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

Accepted Answer

The sporophyte is diploid and produces haploid spores by meiosis.

Question 17

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

Accepted Answer

Formation of recombinant chromosomes

Question 18

In most fungi and some protists, which of the following is true about their sexual life cycle?

Accepted Answer

The only diploid stage is the single-celled zygote.

Question 19

Which of the following best explains why sexual reproduction is advantageous in changing environments?

Accepted Answer

It increases genetic variation, allowing populations to adapt to new conditions.

Question 20

During which stage of meiosis are cohesins cleaved along the chromosome arms, allowing homologs to separate?

Accepted Answer

Anaphase I

Meiosis and Sexual Life Cycles: Study Guide

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