Question 1

Which of the following statements best distinguishes between asexual and sexual reproduction in terms of genetic variation?

Accepted Answer

Asexual reproduction produces offspring that are genetically identical to the parent, while sexual reproduction produces offspring with unique genetic combinations.

Question 2

In humans, which cells are haploid and which are diploid?

Accepted Answer

Gametes are haploid (n = 23), and somatic cells are diploid (2n = 46).

Question 3

Why must fertilization and meiosis alternate in all sexual life cycles?

Accepted Answer

To maintain a constant chromosome number across generations.

Question 4

Which of the following events occurs during meiosis I but not during mitosis?

Accepted Answer

Synapsis and crossing over between homologous chromosomes.

Question 5

During which phase of meiosis do homologous chromosomes align at the metaphase plate?

Accepted Answer

Metaphase I

Question 6

If an organism has a diploid number of 8 (2n = 8), how many possible combinations of chromosomes can be produced by independent assortment during gamete formation?

Accepted Answer

$$2^4 = 16$

Question 7

Which process is responsible for the exchange of genetic material between nonsister chromatids during meiosis?

Accepted Answer

Crossing over

Question 8

A karyotype is useful for which of the following purposes?

Accepted Answer

Identifying the number and structure of chromosomes in a cell.

Question 9

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

Accepted Answer

Autosomes are chromosomes that do not determine sex, while sex chromosomes (X and Y) determine the sex of the individual.

Question 10

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

Accepted Answer

Replication of DNA during S phase

Question 11

In a plant exhibiting alternation of generations, which stage is diploid and produces spores by meiosis?

Accepted Answer

Sporophyte

Question 12

Which of the following statements about sister chromatids and homologous chromosomes is correct?

Accepted Answer

Sister chromatids are identical copies of a chromosome, while homologous chromosomes are similar but not identical and come from different parents.

Question 13

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

Accepted Answer

Anaphase I

Question 14

A mutation in a gene results in a new allele. Which process ensures that this new allele can be shuffled and combined with other alleles in future generations?

Accepted Answer

Sexual reproduction involving meiosis and fertilization

Question 15

Which of the following best explains why offspring from the same parents can look different from each other?

Accepted Answer

Independent assortment, crossing over, and random fertilization create unique combinations of alleles in each offspring.

Question 16

If a sperm cell contains 8 chromosomes, how many chromosomes would be found in a somatic cell of the same organism?

Accepted Answer

$$2 	imes 8 = 16$$

Question 17

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

Accepted Answer

Recombinant chromosomes with genetic material from both parents

Question 18

Which life cycle pattern is characteristic of most fungi and some protists?

Accepted Answer

The zygote is the only diploid stage; the organism is mostly haploid.

Question 19

A human cell in metaphase II of meiosis contains 23 chromosomes, each composed of two sister chromatids. After completion of meiosis II, how many chromosomes and chromatids will each daughter cell have?

Accepted Answer

23 chromosomes, each with one chromatid

Question 20

Which of the following equations correctly represents the number of possible chromosome combinations due to independent assortment in a species with a haploid number $$n$$?

Accepted Answer

$$2^n$$

Meiosis and the Sexual Life Cycle: Study Notes for General Biology

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