Question 1

Which of the following best explains why blending inheritance is not a valid model for genetic inheritance?

Accepted Answer

Blending inheritance suggests that offspring inherit a mix of parental traits, but does not account for the reappearance of recessive traits, which Mendel's experiments demonstrated.

Question 2

A plant breeder crosses a true-breeding tall pea plant (TT) with a true-breeding short pea plant (tt). If the F1 generation is self-fertilized, what proportion of the F2 generation will be heterozygous?

Accepted Answer

$$\frac{1}{3}$$

Question 3

In cats, polydactyly (extra toes) is caused by a dominant allele (P). If a heterozygous polydactylous cat (Pp) mates with a normal-toed cat (pp), what is the probability that a kitten will have extra toes?

Accepted Answer

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

Question 4

Which of the following scenarios best illustrates Mendel's law of independent assortment?

Accepted Answer

A plant with round, yellow seeds produces seeds with all possible combinations of round/wrinkled and yellow/green.

Question 5

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 6

If a genetic disorder is caused by a recessive allele located on the X chromosome, which of the following statements is true?

Accepted Answer

Males are more likely to express the disorder because they have only one X chromosome.

Question 7

A man with hemophilia (an X-linked recessive disorder) and a woman who is a carrier have a son. What is the probability that their son will have hemophilia?

Accepted Answer

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

Question 8

In snapdragons, flower color shows incomplete dominance. If a red-flowered plant (RR) is crossed with a white-flowered plant (WW), what will be the phenotype of the F1 generation?

Accepted Answer

All pink

Question 9

A pedigree shows that deafness is a recessive trait (d). If two hearing parents have a deaf child, what are the genotypes of the parents?

Accepted Answer

Dd and Dd

Question 10

Which of the following best describes a polygenic trait?

Accepted Answer

A trait controlled by multiple genes, each contributing to the phenotype

Question 11

If the probability of having a female child is $$\frac{1}{2}$$ and the probability of having a male child is $$\frac{1}{2}$$, what is the probability that a couple's first child will be female and their next two children will both be male?

Accepted Answer

$$\frac{1}{8}$$

Question 12

Which of the following is an example of codominance?

Accepted Answer

A person with type AB blood expresses both A and B antigens equally.

Question 13

A geneticist observes that two genes are inherited together more often than not. What is the most likely explanation?

Accepted Answer

The genes are linked and located close together on the same chromosome.

Question 14

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

Accepted Answer

The separation of homologous chromosomes during meiosis I.

Question 15

A woman who is heterozygous for the sickle-cell allele is resistant to malaria. This is an example of:

Accepted Answer

Heterozygote advantage

Question 16

Which of the following is true about linked genes?

Accepted Answer

They are located close together on the same chromosome and do not assort independently.

Question 17

A man with an X-linked dominant disorder has children with a woman who does not have the disorder. What proportion of their daughters is expected to have the disorder?

Accepted Answer

100%

Question 18

Which of the following best describes the genotype of an individual who is homozygous for a gene?

Accepted Answer

The individual has two identical alleles for the gene.

Question 19

If two heterozygous individuals (Aa) mate, what is the probability that their offspring will be homozygous recessive?

Accepted Answer

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

Question 20

Which of the following is an example of a phenotype?

Accepted Answer

Blue eyes

Patterns of Inheritance and Mendelian Genetics: Study Guide

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