Question 1

Which of the following best explains how meiosis contributes to genetic diversity in sexually reproducing organisms?

Accepted Answer

By generating new combinations of alleles through independent assortment and crossing over

Question 2

During meiosis, which process is responsible for the exchange of genetic material between homologous chromosomes?

Accepted Answer

Crossing over

Question 3

A gene is best defined as:

Accepted Answer

A discrete unit of inheritance located on a chromosome and composed of a nucleotide sequence along a region of DNA

Question 4

If an organism has a diploid number of 8 ($$2n = 8$$), how many different combinations of chromosomes are possible in its gametes due to independent assortment alone (not including crossing over)?

Accepted Answer

$$2^4 = 16$

Question 5

Which of the following statements about alleles is correct?

Accepted Answer

Alleles are different forms of a gene that may produce proteins with different amino acid sequences

Question 6

A heterozygous individual for a gene located on chromosome 1 and another gene on chromosome 2 can produce gametes with which combinations of alleles, assuming independent assortment?

Accepted Answer

Four possible combinations

Question 7

Which of the following is NOT a mechanism that increases genetic variation during sexual reproduction?

Accepted Answer

Replication of DNA without error

Question 8

The phenotype of an organism is determined by:

Accepted Answer

The proteins produced from its genes

Question 9

Which hypothesis suggests that sexual reproduction is advantageous because it helps eliminate harmful mutations from a population?

Accepted Answer

Purifying selection hypothesis

Question 10

A diploid cell undergoes meiosis. Which of the following best describes the chromosome number in the resulting daughter cells?

Accepted Answer

Each daughter cell has half the number of chromosomes as the parent cell

Question 11

Which of the following scenarios best illustrates the concept of random fertilization increasing genetic diversity?

Accepted Answer

Any sperm can fuse with any egg, resulting in a vast number of possible genetic combinations in the offspring

Question 12

If a human egg contains one of $$2^{23}$$ possible chromosome combinations (not including crossing over), and a sperm also contains one of $$2^{23}$$ possible combinations, how many possible chromosome combinations can result from fertilization (not including crossing over)?

Accepted Answer

$$2^{46}$$

Question 13

Which of the following best describes the relationship between genotype and phenotype?

Accepted Answer

Genotype determines the sequence of DNA, which leads to the production of proteins that result in phenotype

Question 14

Which of the following is an example of independent assortment?

Accepted Answer

The random distribution of maternal and paternal chromosomes into gametes

Question 15

A mutation occurs in the DNA sequence of a gene. Which of the following is a possible consequence?

Accepted Answer

The protein produced by the gene may have a different amino acid sequence

Question 16

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

Accepted Answer

Genetic variation is introduced by crossing over, independent assortment, and random fertilization

Question 17

Which of the following is NOT a benefit of sexual reproduction according to the changing-environment hypothesis?

Accepted Answer

It ensures all offspring are genetically identical to their parents

Question 18

Which of the following best describes the process of crossing over?

Accepted Answer

The exchange of genetic material between homologous, nonsister chromatids during prophase I of meiosis

Question 19

If a cell with genotype $$AaBb$$ undergoes meiosis, what is the expected ratio of gamete genotypes produced, assuming the genes are on different chromosomes and independent assortment occurs?

Accepted Answer

1 AB : 1 Ab : 1 aB : 1 ab

Question 20

Which of the following statements about the relationship between DNA, RNA, and proteins is correct?

Accepted Answer

DNA is transcribed into messenger RNA, which is then translated into protein

Meiosis, Genetic Variation, and the Role of Genes in Biological Diversity

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