Question 1

Which of the following statements best describes Mendel's principle of segregation?

Accepted Answer

The two members of each gene pair must segregate into different gamete cells during the formation of eggs and sperm.

Question 2

In a cross between two heterozygous pea plants for seed shape (Rr x Rr), what is the expected phenotypic ratio in the offspring?

Accepted Answer

$$3:1$$

Question 3

Which experimental result led Mendel to reject the hypothesis of blending inheritance?

Accepted Answer

F$$_2$$ generation showed both parental traits in a 3:1 ratio, not a blend.

Question 4

A dihybrid cross between two pea plants heterozygous for seed shape and seed color (RrYy x RrYy) produces offspring with which expected phenotypic ratio?

Accepted Answer

$$9:3:3:1$$

Question 5

Which of the following best explains the chromosomal theory of inheritance?

Accepted Answer

Genes are located on chromosomes, and their physical separation during meiosis explains Mendel's principles.

Question 6

In fruit flies, red eyes are wild-type and white eyes are a mutation. If a white-eyed male is crossed with a wild-type female, and all F$$_1$$ offspring have red eyes, what does this suggest about the inheritance of the white-eye trait?

Accepted Answer

The white-eye trait is X-linked recessive.

Question 7

Which scenario would most likely result in recombination between linked genes?

Accepted Answer

Genes are located far apart on the same chromosome.

Question 8

A testcross is performed between a pea plant of unknown genotype for seed color and a homozygous recessive plant. If half the offspring are yellow and half are green, what is the genotype of the unknown parent?

Accepted Answer

Heterozygous

Question 9

Which of the following is an example of codominance?

Accepted Answer

Roan cattle displaying both red and white hairs

Question 10

If a trait is controlled by multiple genes and shows continuous variation, what is this type of trait called?

Accepted Answer

Quantitative trait

Question 11

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple traits.

Question 12

A child is born with phenylketonuria (PKU), a recessive disorder. Which dietary intervention can prevent the development of severe symptoms?

Accepted Answer

Low-phenylalanine diet

Question 13

Which of the following is NOT a characteristic of an autosomal dominant trait?

Accepted Answer

Trait is more common in males than females.

Question 14

What is the expected genotypic ratio from a cross between two heterozygous individuals (Rr x Rr)?

Accepted Answer

$$1:2:1$$

Question 15

Which process during meiosis is responsible for Mendel's principle of independent assortment?

Accepted Answer

Random alignment of homologous chromosomes during metaphase I

Question 16

A pedigree shows a trait that skips generations and is more common in males. Which mode of inheritance is most likely?

Accepted Answer

X-linked recessive

Question 17

Which of the following is true about multiple allelism?

Accepted Answer

A gene can have more than two alleles in a population.

Question 18

If two genes are located on the same chromosome and are close together, what is the expected outcome regarding their inheritance?

Accepted Answer

They will be inherited together unless crossing over occurs.

Question 19

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

Accepted Answer

Genotype is the combination of alleles; phenotype is the observable trait.

Question 20

A cross between pure-breeding red-flowered and white-flowered plants produces pink-flowered offspring. What type of inheritance does this demonstrate?

Accepted Answer

Incomplete dominance

Mendel and the Gene: Principles of Inheritance

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