Question 1

Which of the following best describes Mendel's 'law of segregation'?

Accepted Answer

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

Question 2

A pea plant with genotype Pp (P = purple, p = white) is crossed with another Pp plant. What is the probability that an offspring will have white flowers?

Accepted Answer

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

Question 3

Which of the following is an example of codominance?

Accepted Answer

A person with AB blood type expressing both A and B antigens.

Question 4

In a dihybrid cross between two YyRr pea plants (Y = yellow, y = green, R = round, r = wrinkled), what is the probability of obtaining an offspring with genotype yyrr?

Accepted Answer

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

Question 5

Which of the following best explains why cystic fibrosis is considered a pleiotropic disorder?

Accepted Answer

It affects multiple organ systems due to a single gene mutation.

Question 6

A testcross is performed between a pea plant with purple flowers of unknown genotype and a white-flowered plant (pp). If all offspring have purple flowers, what is the genotype of the purple-flowered parent?

Accepted Answer

PP

Question 7

Which of the following scenarios illustrates epistasis?

Accepted Answer

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

Question 8

If two carriers of albinism (Aa x Aa) have a child, what is the probability that the child will be phenotypically normal?

Accepted Answer

$$\frac{3}{4}$$

Question 9

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes contribute additively to a single phenotypic trait.

Question 10

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

Accepted Answer

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

Question 11

Which of the following is NOT a reason why Mendel chose pea plants for his experiments?

Accepted Answer

They have a long generation time.

Question 12

A heterozygous individual for sickle-cell disease (Ss) is generally healthy but has some resistance to malaria. What is this an example of?

Accepted Answer

Heterozygote advantage

Question 13

Which of the following best describes the multiplication rule in probability as applied to genetics?

Accepted Answer

The probability of two independent events occurring together is the product of their individual probabilities.

Question 14

In a cross between two AaBbCc individuals, what is the probability of producing an offspring with genotype aabbcc?

Accepted Answer

$$\frac{1}{64}$$

Question 15

Which of the following is true regarding the relationship between genotype and phenotype?

Accepted Answer

Different genotypes can produce the same phenotype.

Question 16

A geneticist observes a 9:3:3:1 phenotypic ratio in the F2 generation of a cross. What does this indicate about the genes involved?

Accepted Answer

The genes assort independently.

Question 17

Which of the following is an example of a multifactorial trait?

Accepted Answer

Skin color influenced by both genes and sunlight exposure

Question 18

If a dominant allele causes a lethal disease, why are such alleles rare in the population?

Accepted Answer

Affected individuals often die before reproducing.

Question 19

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote phenotype is intermediate between the two homozygotes.

Question 20

A pedigree shows a trait that skips generations and appears only in homozygous individuals. What is the most likely mode of inheritance?

Accepted Answer

Recessive

Mendelian Genetics: Principles and Extensions

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