Question 1

Which of the following statements best explains 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 $$Pp ($$where $$P is $$dominant for purple flowers and $$p is $$recessive for white flowers) is crossed with a plant with genotype $$pp. $$What is the expected ratio of purple to white flowers in the offspring?

Accepted Answer

$$1:1$$

Question 3

Which of the following best describes a testcross and its purpose?

Accepted Answer

Breeding an individual with the dominant phenotype with a homozygous recessive individual to determine the genotype of the dominant individual.

Question 4

In a dihybrid cross between two individuals with genotype $$YyRr$$, what is the probability of obtaining an offspring with genotype $$YYRR$$?

Accepted Answer

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

Question 5

Which of the following scenarios demonstrates the law of independent assortment?

Accepted Answer

Alleles for seed color and seed shape segregate independently during gamete formation.

Question 6

A couple, both of whom have a sibling affected by a recessive genetic disorder, want to know the probability that their child will have the disorder. Assuming neither parent is affected, what is the probability their child will be affected?

Accepted Answer

$$\frac{1}{9}$$

Question 7

Which of the following is an example of pleiotropy?

Accepted Answer

A gene that affects multiple symptoms in cystic fibrosis.

Question 8

In Labrador retrievers, coat color is determined by two genes: one for pigment color ($$B$$ for black, $$b$$ for brown) and one for pigment deposition ($$E$$ for color, $$e$$ for no color). What is the expected phenotypic ratio in the $$F_2$$ generation when two $$BbEe$$ dogs are crossed?

Accepted Answer

$$9$$ black : $$3$$ chocolate : $$4$$ yellow

Question 9

Which of the following inheritance patterns is demonstrated when the phenotype of heterozygotes is intermediate between the two homozygotes?

Accepted Answer

Incomplete dominance

Question 10

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

Accepted Answer

A or B

Question 11

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes independently affect a single trait.

Question 12

If a heterozygous plant ($$Rr) is $$self-pollinated, what is the probability that the offspring will be heterozygous?

Accepted Answer

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

Question 13

Which of the following is true about dominant alleles?

Accepted Answer

Dominant alleles are not necessarily more common than recessive alleles in a population.

Question 14

Which rule is used to calculate the probability that two independent events will both occur?

Accepted Answer

Multiplication rule

Question 15

A genetic counselor is helping a couple where both are carriers for cystic fibrosis. What is the probability that their child will be a carrier but not affected?

Accepted Answer

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

Question 16

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

Accepted Answer

Height influenced by multiple genes and environment

Question 17

Which of the following best describes codominance?

Accepted Answer

Both alleles are expressed in the phenotype in separate, distinguishable ways.

Question 18

In a pedigree analysis, which pattern would you expect for a recessively inherited disorder?

Accepted Answer

Affected individuals are usually homozygous for the allele and often born to carrier parents.

Question 19

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

Accepted Answer

Phenotype reflects both genotype and environmental history.

Question 20

A man with achondroplasia (a dominant disorder) marries a woman who does not have the disorder. What is the probability that their child will have achondroplasia?

Accepted Answer

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

Mendel and the Gene Idea: Principles of Inheritance

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