Question 1

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

Accepted Answer

Because sexual reproduction involves the combination of genes from two parents, leading to unique gene combinations.

Question 2

A human somatic cell contains 46 chromosomes. How many chromosomes are present in a human gamete?

Accepted Answer

$$23$$

Question 3

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

Accepted Answer

Meiosis

Question 4

What is the significance of crossing over during prophase I of meiosis?

Accepted Answer

It increases genetic variation by exchanging DNA between homologous chromosomes.

Question 5

If a diploid cell of a mosquito (Aedes aegypti) has $$2n = 6$$ chromosomes, how many chromosomes are present in each gamete after meiosis?

Accepted Answer

$$3$$

Question 6

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry genes controlling the same inherited characters but may have different alleles.

Question 7

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

Accepted Answer

Anaphase I

Question 8

Which equation 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 9

A geneticist is studying a plant species with a diploid number of $$2n = 8. $$How many genetically unique gametes can be produced by independent assortment alone?

Accepted Answer

$$2^4 = 16$

Question 10

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 11

In humans, which chromosomes determine the sex of an individual?

Accepted Answer

Sex chromosomes (X and Y)

Question 12

A cell with a diploid number of $$2n = 10$$ undergoes meiosis. How many chromosomes will each resulting gamete contain?

Accepted Answer

$$5$$

Question 13

Which stage of meiosis is most directly responsible for the independent assortment of chromosomes?

Accepted Answer

Metaphase I

Question 14

A mutation occurs in a gene located at a specific locus on a chromosome. What is the most likely result of this mutation?

Accepted Answer

A new allele of the gene is created.

Question 15

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 16

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

Accepted Answer

Pairing of homologous chromosomes and crossing over

Question 17

Why is random fertilization a significant source of genetic variation?

Accepted Answer

Because any sperm can fuse with any egg, creating a vast number of possible genetic combinations.

Question 18

In the alternation of generations life cycle seen in plants, which process produces haploid spores from a diploid sporophyte?

Accepted Answer

Meiosis

Question 19

Which of the following best explains why natural selection can act more efficiently in sexually reproducing populations?

Accepted Answer

Sexual reproduction increases genetic variation, providing more raw material for selection.

Question 20

A scientist observes a cell with homologous chromosomes aligned at the metaphase plate, each chromosome consisting of two sister chromatids. Which phase is this cell in?

Accepted Answer

Metaphase I of meiosis

Meiosis and the Basis of Heredity: Chromosomal Mechanisms and Genetic Variation

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