Question 1

Which of the following best explains why the blending hypothesis of inheritance was rejected by Mendel's experiments?

Accepted Answer

It could not explain how traits that disappear in one generation can reappear in later generations.

Question 2

A true-breeding purple-flowered pea plant is crossed with a true-breeding white-flowered pea plant. All offspring in the F1 generation have purple flowers. What is the genotype of the F1 generation?

Accepted Answer

Pp

Question 3

According to Mendel’s law of segregation, what happens to allele pairs during the formation of gametes?

Accepted Answer

Allele pairs separate so that each gamete carries only one allele for each gene.

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 in the F2 generation according to Mendel’s law of independent assortment?

Accepted Answer

$$9:3:3:1$$

Question 5

A testcross is performed between a black Labrador retriever of unknown genotype (B_?) and a chocolate Labrador (bb). If all offspring are black, what is the genotype of the black Labrador?

Accepted Answer

BB

Question 6

If two parents are both heterozygous for albinism (Aa), what is the probability that their child will have albinism (aa)?

Accepted Answer

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

Question 7

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red-flowered and white-flowered snapdragons produces pink-flowered offspring.

Question 8

A woman with type A blood (genotype $$I^A i) $$and a man with type B blood (genotype $$I^B i) $$have a child. Which blood type is NOT possible for their child?

Accepted Answer

None of the above; all blood types (A, B, AB, O) are possible.

Question 9

Sickle-cell disease is an example of pleiotropy because:

Accepted Answer

A single gene affects multiple phenotypic traits, such as anemia, organ damage, and resistance to malaria.

Question 10

Human skin color is an example of polygenic inheritance. If two parents with genotype $$AaBbCc$$ have a child, what is the probability that the child will have the genotype $$AABbcc$$?

Accepted Answer

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

Question 11

Which phase of meiosis is the physical basis for Mendel’s law of segregation?

Accepted Answer

Anaphase I

Question 12

Linked genes do not follow Mendel’s law of independent assortment because:

Accepted Answer

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

Question 13

A geneticist observes that two genes have a recombination frequency of 9%. What does this indicate about their location?

Accepted Answer

They are relatively close together on the same chromosome.

Question 14

In humans, which chromosome combination determines a male?

Accepted Answer

XY

Question 15

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

Accepted Answer

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

Question 16

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

Accepted Answer

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

Question 17

Which real-world scenario is an example of environmental influence on genetic traits?

Accepted Answer

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

Question 18

Why are X-linked recessive disorders 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 19

Which of the following is a benefit of chorionic villus sampling (CVS) compared to amniocentesis?

Accepted Answer

CVS can be performed earlier in pregnancy and results are available sooner.

Question 20

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

Accepted Answer

Type A or type B

Patterns of Inheritance: Mendelian Genetics and Beyond

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