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 pea 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

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

Accepted Answer

A plant with genotype $$RrYy$$ produces gametes $$RY$$, $$Ry$$, $$rY$$, and $$ry in $$equal proportions.

Question 4

In a monohybrid cross between two heterozygous individuals ($$Aa 	imes Aa$$), what is the probability of producing an offspring with the homozygous recessive genotype?

Accepted Answer

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

Question 5

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 6

If two genes are located on different chromosomes, what is the expected phenotypic ratio in the F2 generation of a dihybrid cross ($$AaBb 	imes AaBb) $$assuming independent assortment?

Accepted Answer

$$9:3:3:1$$

Question 7

A woman is a carrier for a recessive genetic disorder (genotype $$Nn) $$and her partner is homozygous normal ($$NN). $$What is the probability that their child will have the disorder?

Accepted Answer

$$0$$

Question 8

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes independently affect a single trait, resulting in a range of phenotypes.

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

Which of the following is an example of epistasis?

Accepted Answer

A gene for pigment deposition masks the expression of a gene for pigment color in Labrador retrievers.

Question 11

If a test cross between a plant with an unknown genotype and a homozygous recessive plant produces both dominant and recessive phenotypes, what is the genotype of the unknown plant?

Accepted Answer

Heterozygous

Question 12

Which of the following best explains why Mendel's experiments with pea plants were successful in revealing the basic principles of inheritance?

Accepted Answer

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

Question 13

A couple has a child with a rare autosomal recessive disorder. Neither parent shows symptoms. What is the probability that their next child will also have the disorder?

Accepted Answer

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

Question 14

Which of the following is true about the multiplication rule in probability as applied to genetics?

Accepted Answer

It is used to calculate the probability of two independent events both occurring.

Question 15

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

Accepted Answer

A or B

Question 16

Which of the following is an example of a quantitative (polygenic) trait?

Accepted Answer

Skin color

Question 17

If a gene has multiple phenotypic effects, this is known as:

Accepted Answer

Pleiotropy

Question 18

In a dihybrid cross ($$AaBb 	imes AaBb$$), what is the probability of producing an offspring with genotype $$aabb$$?

Accepted Answer

$$\frac{1}{16}$$

Question 19

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 20

A genetic counselor is analyzing a pedigree for a family with a history of a certain disorder. The disorder appears in both males and females, skips generations, and affected individuals are born to unaffected parents. What is the most likely mode of inheritance?

Accepted Answer

Autosomal recessive

Mendel and the Gene Idea: Study Guide and Key Concepts

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