Question 1

Which of the following statements best describes the chromosome theory of inheritance as proposed by Sutton and Boveri?

Accepted Answer

Genes are located on chromosomes, and genetic information is transmitted from one generation to the next through chromosomes.

Question 2

Mendel chose the garden pea as his model organism for genetic experiments primarily because:

Accepted Answer

Peas are inexpensive, easy to grow, have a short generation time, and produce many seeds.

Question 3

Which hypothesis did Mendel’s monohybrid cross experiments directly contradict?

Accepted Answer

Blending inheritance

Question 4

In a monohybrid cross between two heterozygous pea plants (Rr x Rr), what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$3:1$$

Question 5

Which of the following best explains the principle of segregation?

Accepted Answer

Alleles of a gene separate into different gametes during meiosis.

Question 6

A testcross is used to determine the genotype of a parent with a dominant phenotype. Which cross would you perform?

Accepted Answer

Cross the dominant phenotype individual with a homozygous recessive individual.

Question 7

If a gene is located on the X chromosome and shows recessive inheritance, which of the following is most likely true?

Accepted Answer

Males are more likely to express the trait than females.

Question 8

Which of the following is an example of codominance?

Accepted Answer

AB blood type in humans, where both A and B antigens are expressed.

Question 9

A geneticist observes that two genes are often inherited together. What is the most likely explanation?

Accepted Answer

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

Question 10

Which of the following best describes pleiotropy?

Accepted Answer

A single gene influences multiple traits.

Question 11

In a dihybrid cross between two heterozygous individuals (RrYy x RrYy), what is the expected phenotypic ratio in the F2 generation according to Mendel’s principle of independent assortment?

Accepted Answer

$$9:3:3:1$$

Question 12

Which of the following scenarios is an example of incomplete dominance?

Accepted Answer

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

Question 13

Which of the following is true about quantitative traits?

Accepted Answer

They are influenced by multiple genes and often show continuous variation.

Question 14

A woman who is a carrier for an X-linked recessive trait and a man who does not have the trait have a son. What is the probability that their son will express the trait?

Accepted Answer

$$0.5$$

Question 15

Which of the following best explains why crossing over increases genetic diversity?

Accepted Answer

It creates new combinations of alleles on chromosomes during meiosis.

Question 16

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 17

Which of the following is a real-world example of environmental influence on phenotype?

Accepted Answer

Individuals with phenylketonuria (PKU) develop normally if placed on a low-phenylalanine diet.

Question 18

If a trait is autosomal recessive, which of the following is true?

Accepted Answer

Individuals with the trait must be homozygous recessive.

Question 19

Which of the following best describes epistasis?

Accepted Answer

The expression of one gene is masked by the genotype of another gene.

Question 20

Which of the following is NOT a reason Mendel’s pea plants were a good model organism?

Accepted Answer

They have a long generation time.

Mendel and the Gene: Foundations of Classical Genetics

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