Question 1

Which of the following best describes the difference between somatic cells and gametes in humans?

Accepted Answer

Somatic cells are diploid (2n), while gametes are haploid (n).

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.

Question 3

If a human cell has 46 chromosomes, how many chromosomes will each gamete have after meiosis?

Accepted Answer

23

Question 4

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 5

A zygote is formed by the fusion of two gametes. What is the chromosome number of the zygote in humans?

Accepted Answer

46

Question 6

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

Accepted Answer

Replication of DNA during mitosis

Question 7

What is the main evolutionary advantage of sexual reproduction over asexual reproduction?

Accepted Answer

It increases genetic diversity among offspring.

Question 8

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry genes for the same traits at the same loci.

Question 9

During which stage of meiosis do homologous chromosomes separate?

Accepted Answer

Anaphase I

Question 10

A genetic disorder is caused by a mutation in a gene located on the X chromosome. Which of the following individuals is most likely to express the disorder if the mutation is recessive?

Accepted Answer

A male with one mutated X chromosome

Question 11

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

Accepted Answer

Synapsis and crossing over

Question 12

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

Accepted Answer

$$2^4 = 16$

Question 13

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

Accepted Answer

Genetic variation arises from independent assortment, crossing over, and random fertilization.

Question 14

Which process restores the diploid number of chromosomes in the human life cycle?

Accepted Answer

Fertilization

Question 15

A cell with a diploid number of 10 undergoes meiosis. How many chromosomes will each of the resulting daughter cells have?

Accepted Answer

5

Question 16

Which of the following is true about the products of meiosis?

Accepted Answer

They are haploid and genetically distinct from each other and the parent cell.

Question 17

In a human male, which chromosome combination is found in his gametes?

Accepted Answer

Each gamete contains either an X or a Y chromosome, but not both.

Question 18

Which of the following best describes the role of meiosis in the human life cycle?

Accepted Answer

It reduces the chromosome number by half, producing haploid gametes.

Question 19

A scientist observes a cell in which homologous chromosomes are paired and exchanging genetic material. Which stage of meiosis is being observed?

Accepted Answer

Prophase I

Question 20

Which of the following statements about fertilization is correct?

Accepted Answer

Fertilization restores the diploid number of chromosomes by combining two haploid gametes.

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

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