Question 1

Which of the following best describes Mendel's Law of Segregation?

Accepted Answer

Two alleles for a heritable character separate during gamete formation and end up in different gametes.

Question 2

A plant with genotype $$Tt ($$where $$T is $$tall and $$t is $$short) is self-fertilized. What is the expected phenotypic ratio of tall to short offspring?

Accepted Answer

$$3:1$$

Question 3

In a dihybrid cross between two heterozygous pea plants ($$YyRr 	imes YyRr$$), where $$Y = $$yellow, $$y = $$green, $$R = $$round, $$r = $$wrinkled, what is the expected phenotypic ratio among the offspring?

Accepted Answer

$$9:3:3:1$$

Question 4

Which of the following scenarios best illustrates the Law of Independent Assortment?

Accepted Answer

The inheritance of seed color does not affect the inheritance of seed shape in pea plants.

Question 5

If two parents are both carriers for cystic fibrosis (an autosomal recessive disorder), what is the probability that their child will have cystic fibrosis?

Accepted Answer

$$1/4$$

Question 6

Which of the following is an example of incomplete dominance?

Accepted Answer

A red-flowered plant crossed with a white-flowered plant produces pink-flowered offspring.

Question 7

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

Accepted Answer

$$1/2$$

Question 8

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes independently affect a single trait, resulting in continuous variation.

Question 9

In a pedigree analysis, which pattern suggests an autosomal dominant inheritance?

Accepted Answer

The trait appears in every generation and affected individuals have at least one affected parent.

Question 10

If the probability of inheriting allele $$A$$ from one parent is $$1/2$$ and the probability of inheriting allele $$B$$ from the other parent is $$1/2$$, what is the probability of inheriting both $$A$$ and $$B$$?

Accepted Answer

$$1/4$$

Question 11

Which of the following is an example of epistasis?

Accepted Answer

A gene at one locus alters the phenotypic expression of a gene at a second locus.

Question 12

A couple has three children. What is the probability that all three are boys? (Assume the probability of having a boy is $$1/2$$ for each child.)

Accepted Answer

$$1/8$$

Question 13

Which of the following best explains why Mendel's pea plant experiments were successful in revealing basic patterns of inheritance?

Accepted Answer

He focused on traits controlled by single genes with clear dominant and recessive alleles.

Question 14

Which of the following genotypes represents a test cross?

Accepted Answer

Crossing an individual with unknown genotype with a homozygous recessive individual.

Question 15

A man with blood type $$AB$$ and a woman with blood type $$O$$ have a child. What are the possible blood types for their child?

Accepted Answer

Type $$A or $$Type $$B$$

Question 16

Which of the following is a real-world example of pleiotropy?

Accepted Answer

Sickle-cell disease, where one gene affects both hemoglobin structure and resistance to malaria.

Question 17

If a trait is determined by two genes, each with two alleles, and both genes show complete dominance, how many different phenotypes are possible?

Accepted Answer

Four

Question 18

Which of the following statements about dominant and recessive alleles is correct?

Accepted Answer

Dominant alleles mask the expression of recessive alleles in heterozygotes.

Question 19

A woman with genotype $$Bb ($$where $$B is $$brown eyes and $$b is $$blue eyes) marries a man with genotype $$bb. $$What is the probability that their child will have blue eyes?

Accepted Answer

$$1/2$$

Question 20

Which of the following best describes the use of a Punnett square?

Accepted Answer

To predict the probability of offspring genotypes and phenotypes from parental crosses.

Mendel and the Gene Idea: Study Guide and Key Concepts

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