Question 1

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

Accepted Answer

The two alleles for a heritable character separate during gamete formation, so that each gamete carries only one allele for each gene.

Question 2

A plant with genotype $$Pp ($$where $$P is $$dominant for purple flowers and $$p is $$recessive for white flowers) is self-fertilized. What is the expected phenotypic ratio of the offspring?

Accepted Answer

$$3$$ purple : $$1$$ white

Question 3

In a dihybrid cross between two double heterozygotes ($$RrYy 	imes RrYy$$), what is the expected phenotypic ratio among the F2 offspring?

Accepted Answer

$$9:3:3:1$$

Question 4

A man with type AB blood ($$I^A I^B) $$and a woman with type O blood ($$ii) $$have a child. What are the possible blood types of their child?

Accepted Answer

A or B

Question 5

Which of the following is an example of pleiotropy?

Accepted Answer

A single gene affecting both red blood cell shape and resistance to malaria in sickle-cell disease.

Question 6

A testcross is performed between a black Labrador retriever of unknown genotype and a chocolate Labrador ($$bb). If $$all offspring are black, what is the genotype of the black parent?

Accepted Answer

BB

Question 7

Which of the following best explains why linked genes do not always show perfect linkage in offspring?

Accepted Answer

Crossing over during meiosis can separate linked genes, resulting in recombinant phenotypes.

Question 8

A woman who is a carrier for hemophilia ($$X^H X^h) $$and a man without hemophilia ($$X^H Y) $$have a son. What is the probability that their son will have hemophilia?

Accepted Answer

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

Question 9

Which of the following is an example of polygenic inheritance?

Accepted Answer

Skin color in humans

Question 10

If two parents are both heterozygous for a recessive genetic disorder ($$Dd$$), what is the probability that their child will be affected by the disorder?

Accepted Answer

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

Question 11

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 12

A woman with genotype $$IAi$$ and a man with genotype $$IBi$$ have a child. What is the probability that the child will have type O blood?

Accepted Answer

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

Question 13

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote has a phenotype intermediate between the two homozygotes.

Question 14

A genetic counselor is analyzing a pedigree for a family with a history of a recessive disorder. Which pattern would most likely indicate a recessive inheritance?

Accepted Answer

Affected individuals often have unaffected parents.

Question 15

Which of the following best illustrates the relationship between structure and function in biology?

Accepted Answer

The sickle-cell mutation changing the shape of hemoglobin and affecting its function.

Question 16

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

Accepted Answer

Males are more likely to express the trait than females.

Question 17

Which of the following is a real-world example of the law of independent assortment?

Accepted Answer

The inheritance of flower color and seed shape in pea plants occurs independently.

Question 18

A couple, both with normal hearing, have a child who is deaf. Deafness is a recessive trait. What are the genotypes of the parents?

Accepted Answer

Both are heterozygous.

Question 19

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes contribute additively to a single trait.

Question 20

Which of the following is true about wild-type traits?

Accepted Answer

They are the traits most often seen in nature, regardless of dominance.

Patterns of Inheritance: Mendelian Genetics and Beyond

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