Question 1

Which of the following best describes the 'particulate' hypothesis as proposed by Mendel?

Accepted Answer

It proposes that parents pass on discrete heritable units that retain their separate identities in offspring.

Question 2

In Mendel's classic pea plant experiments, what was the phenotypic ratio observed in the F2 generation when crossing two heterozygous purple-flowered plants (Pp x Pp)?

Accepted Answer

$$3:1$$

Question 3

A plant with genotype Pp is crossed with a plant with genotype pp. What is the expected ratio of purple to white flowers in the offspring, assuming purple is dominant?

Accepted Answer

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

Question 4

Which of the following statements about Mendel's law of segregation is correct?

Accepted Answer

It states that the two alleles for a heritable character separate during gamete formation and end up in different gametes.

Question 5

A testcross is performed between a pea plant with an unknown genotype for purple flowers and a white-flowered plant. If half the offspring are purple and half are white, what is the genotype of the purple-flowered parent?

Accepted Answer

Pp

Question 6

Which of the following best illustrates the law of independent assortment?

Accepted Answer

The alleles for flower color and seed shape segregate independently during gamete formation.

Question 7

In a dihybrid cross between two heterozygous pea plants (YyRr x YyRr), what is the expected phenotypic ratio among the offspring?

Accepted Answer

$$9:3:3:1$$

Question 8

A woman with blood type AB has a child with a man who is blood type O. Which of the following blood types could their child have?

Accepted Answer

A or B

Question 9

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white snapdragons produces pink flowers.

Question 10

A gene that affects multiple, seemingly unrelated phenotypic traits is said to be:

Accepted Answer

Pleiotropic

Question 11

In Labrador retrievers, coat color is determined by two genes: one for pigment color (B = black, b = brown) and one for pigment deposition (E = color, e = no color). What is the expected coat color of a dog with genotype bbEe?

Accepted Answer

Brown

Question 12

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes have an additive effect on a single phenotypic character.

Question 13

A hydrangea plant with the same genotype produces blue flowers in acidic soil and pink flowers in alkaline soil. This is an example of:

Accepted Answer

Environmental influence on phenotype (norm of reaction)

Question 14

If a true-breeding red-flowered plant ($$C^RC^R) is $$crossed with a true-breeding white-flowered plant ($$C^WC^W$$), and the F1 generation is all pink ($$C^RC^W$$), what will be the phenotypic ratio in the F2 generation after self-pollination?

Accepted Answer

$$1$$ red : $$2$$ pink : $$1$$ white

Question 15

Which of the following statements about genotype and phenotype is correct?

Accepted Answer

Two organisms with the same phenotype can have different genotypes.

Question 16

A couple, both heterozygous for a recessive genetic disorder (Aa), want to know the probability that their child will be affected. What is the probability?

Accepted Answer

$$1/4$$

Question 17

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

Accepted Answer

ABO blood group in humans, where both A and B antigens are expressed

Question 18

A pedigree analysis is most useful for which of the following purposes?

Accepted Answer

Tracing the inheritance pattern of a trait across generations in a family

Question 19

If a plant is homozygous for a gene, which of the following is true?

Accepted Answer

It has two identical alleles for the gene.

Question 20

Which of the following equations would you use to calculate the probability of two independent events both occurring, such as inheriting two unlinked traits?

Accepted Answer

Multiplication rule: $$P(A 	ext{ and } B) = P(A) 	imes P(B)$$

Mendel and the Gene Idea: Principles of Inheritance

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