Question 1

Which of the following best explains why sexual reproduction leads to greater genetic variation than asexual reproduction?

Accepted Answer

Sexual reproduction involves the fusion of gametes from two parents, allowing for independent assortment and crossing over during meiosis.

Question 2

During meiosis, which stage is primarily responsible for the law of independent assortment?

Accepted Answer

Metaphase I, when homologous chromosome pairs align independently at the metaphase plate.

Question 3

A plant with genotype $$RrYy ($$where R = round, r = wrinkled, Y = yellow, y = green) is crossed with a plant with genotype $$rryy. $$What is the expected phenotypic ratio of the offspring if the genes assort independently?

Accepted Answer

1 round yellow : 1 round green : 1 wrinkled yellow : 1 wrinkled green

Question 4

Which of the following scenarios best illustrates the concept of incomplete dominance?

Accepted Answer

A cross between red-flowered and white-flowered snapdragons produces pink-flowered offspring.

Question 5

Which of the following best describes the difference between a gene and an allele?

Accepted Answer

A gene is a segment of DNA that codes for a trait, while an allele is a specific version of that gene.

Question 6

A woman who is a carrier for a recessive X-linked disorder (genotype $$X^NX^n) $$and a man who is unaffected ($$X^NY) $$have a child. What is the probability that their son will have the disorder?

Accepted Answer

$$\frac{1}{2}$$

Question 7

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

Accepted Answer

Recombinant chromosomes that contain genetic material from both homologous chromosomes.

Question 8

A pedigree shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 9

Which of the following best explains how Mendel's law of segregation is related to chromosome behavior during meiosis?

Accepted Answer

During anaphase I, homologous chromosomes separate so that each gamete receives only one allele of each gene.

Question 10

A geneticist observes that two genes are inherited together more often than expected by chance. What is the most likely explanation?

Accepted Answer

The genes are located close together on the same chromosome (linked genes).

Question 11

Which of the following is an example of polygenic inheritance?

Accepted Answer

Human skin color, which is influenced by multiple genes.

Question 12

If the recombination frequency between two genes is 10%, what does this indicate about their physical relationship on a chromosome?

Accepted Answer

The genes are relatively close together on the same chromosome.

Question 13

Which of the following best describes the outcome of a test cross between an individual with an unknown genotype and a homozygous recessive individual?

Accepted Answer

The phenotypes of the offspring reveal whether the unknown individual is homozygous or heterozygous.

Question 14

Which of the following is a benefit of genetic variation in sexually reproducing populations?

Accepted Answer

It increases the ability of a population to adapt to changing environments.

Question 15

A man with blood type A (genotype $$I^A i) $$and a woman with blood type B (genotype $$I^B i) $$have a child. What is the probability that the child will have blood type O?

Accepted Answer

$$\frac{1}{4}$$

Question 16

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

Accepted Answer

Binary fission

Question 17

A woman with genotype $$AaBb ($$for two unlinked genes) produces an egg. What is the probability that the egg contains the $$ab$$ combination?

Accepted Answer

$$\frac{1}{4}$$

Question 18

Which of the following best explains why alterations in chromosome number can lead to changes in phenotype?

Accepted Answer

Changes in chromosome number can result in abnormal gene dosage, affecting the expression of multiple genes.

Question 19

Which of the following is true regarding sex determination in mammals?

Accepted Answer

The presence of a Y chromosome typically determines maleness.

Question 20

A couple has a child with a rare genetic disorder. Neither parent shows symptoms, but both have a sibling with the disorder. What is the most likely mode of inheritance?

Accepted Answer

Autosomal recessive

Genetics, Inheritance, and Cell Division: Study Guide for Chapters 10–12

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