Question 1

Which of the following best explains why siblings produced by the same parents are not genetically identical?

Accepted Answer

Because independent assortment and crossing over during meiosis create unique combinations of alleles in gametes.

Question 2

A human cell containing 22 autosomes and an X chromosome is:

Accepted Answer

A gamete (egg cell)

Question 3

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 4

If a diploid organism has a chromosome number of $$2n = 8$$, how many possible combinations of chromosomes can result from independent assortment during meiosis (ignoring crossing over)?

Accepted Answer

$$2^4 = 16$

Question 5

Which of the following statements about meiosis is FALSE?

Accepted Answer

Homologous chromosomes separate during meiosis II.

Question 6

A geneticist observes a karyotype with 47 chromosomes, including three copies of chromosome 21. Which process most likely failed to occur properly?

Accepted Answer

Proper separation of homologous chromosomes during anaphase I (nondisjunction)

Question 7

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

Accepted Answer

Asexual reproduction produces genetically identical offspring, while sexual reproduction increases genetic variation.

Question 8

Which event during meiosis is primarily responsible for the independent assortment of alleles?

Accepted Answer

Alignment of homologous pairs at the metaphase plate during metaphase I

Question 9

A mutation occurs in a gene located on chromosome 15. In which type of cell must this mutation occur to be passed on to the next generation?

Accepted Answer

A gamete (egg or sperm)

Question 10

Which of the following equations correctly represents the chromosome number in human somatic and gamete cells?

Accepted Answer

Somatic cells: $$2n = 46$$, Gametes: $$n = 23$$

Question 11

Which process ensures that the chromosome number of a species remains constant across generations?

Accepted Answer

Meiosis followed by fertilization

Question 12

Which of the following is NOT a mechanism that contributes to genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA during interphase

Question 13

A cell with a diploid number of $$2n = 12$$ undergoes meiosis. How many chromosomes will each resulting gamete contain?

Accepted Answer

$$6$$

Question 14

Which of the following best explains the evolutionary significance of sexual reproduction?

Accepted Answer

It increases genetic variation, providing raw material for natural selection.

Question 15

Which of the following events occurs during anaphase II of meiosis?

Accepted Answer

Sister chromatids separate and move to opposite poles.

Question 16

A woman is a carrier for a genetic disorder located on the X chromosome. Which of the following best describes how this trait can be passed to her children?

Accepted Answer

She can pass the trait to both sons and daughters, but sons are more likely to express the disorder if they inherit the affected X chromosome.

Question 17

Which of the following is true regarding the products of meiosis in humans?

Accepted Answer

Each gamete contains one set of chromosomes and is genetically unique.

Question 18

Which of the following best describes a karyotype?

Accepted Answer

An ordered display of the pairs of homologous chromosomes from a cell.

Question 19

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

Accepted Answer

Separation of sister chromatids

Question 20

A scientist observes that a certain plant species can reproduce both sexually and asexually. Which of the following is a likely advantage of sexual reproduction for this species?

Accepted Answer

It increases genetic diversity, which may enhance adaptation to changing environments.

Meiosis and Sexual Life Cycles: Mechanisms of Heredity and Genetic Variation

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