Question 1

Which of the following best explains why the blending hypothesis was rejected in favor of Mendel’s particulate theory of inheritance?

Accepted Answer

The blending hypothesis could not explain how traits that disappear in one generation can reappear in later generations.

Question 2

A true-breeding pea plant with purple flowers is crossed with a true-breeding pea plant with white flowers. All F1 offspring have purple flowers. If two F1 plants are crossed, what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$3:1 ($$purple:white)

Question 3

Which statement correctly describes the law of segregation?

Accepted Answer

Allele pairs separate from each other during the production of gametes.

Question 4

In a dihybrid cross between two individuals heterozygous for both seed color (Yy) and seed shape (Rr), what is the expected phenotypic ratio among the F2 offspring?

Accepted Answer

$$9:3:3:1$$

Question 5

A geneticist performs a testcross between a black Labrador retriever of unknown genotype and a chocolate Labrador retriever that is homozygous recessive. If all offspring are black, what is the genotype of the black parent?

Accepted Answer

$$BB$$

Question 6

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white snapdragons produces pink flowers.

Question 7

Which inheritance pattern is illustrated by the ABO blood group system in humans?

Accepted Answer

Multiple alleles and codominance

Question 8

Sickle-cell disease is an example of pleiotropy because:

Accepted Answer

A single gene affects multiple phenotypic traits.

Question 9

Which of the following best describes polygenic inheritance?

Accepted Answer

A single phenotypic character is affected by two or more genes.

Question 10

A woman who is a carrier for the X-linked recessive allele for color blindness marries a man with normal vision. What is the probability that their son will be color blind?

Accepted Answer

$$0.5$$

Question 11

Which of the following statements about linked genes is correct?

Accepted Answer

Linked genes are located close together on the same chromosome and tend to be inherited together.

Question 12

If the recombination frequency between two genes is $$12\%$$, what does this indicate about their location?

Accepted Answer

The genes are relatively close together on the same chromosome.

Question 13

Which of the following best explains why most X-linked disorders are more common in males than in females?

Accepted Answer

Males have only one X chromosome, so a single recessive allele will cause the disorder.

Question 14

Which of the following is an example of a dominant human genetic disorder?

Accepted Answer

Achondroplasia

Question 15

A couple has a child with albinism, a recessive disorder. Both parents have normal pigmentation. What are the genotypes of the parents?

Accepted Answer

Both are heterozygous ($$Aa)$$

Question 16

Which of the following best describes the chromosomal theory of inheritance?

Accepted Answer

Genes occupy specific loci on chromosomes, and chromosomes undergo segregation and independent assortment during meiosis.

Question 17

Which rule would you use to calculate the probability of obtaining a plant with yellow, round seeds from a dihybrid cross ($$YyRr 	imes YyRr$$)?

Accepted Answer

The rule of multiplication

Question 18

Which of the following is a real-world example of environmental influence on phenotype?

Accepted Answer

The sex of some reptiles is determined by the temperature at which eggs are incubated.

Question 19

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

Accepted Answer

Type A or type B

Question 20

Which of the following statements about the Y chromosome is true?

Accepted Answer

It is passed from father to son and can be used to trace paternal ancestry.

Patterns of Inheritance: Mendelian Genetics and Beyond

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