Question 1

Which of the following best describes Mendel's Law of Segregation?

Accepted Answer

Alleles for a heritable character separate during gamete formation, so each gamete receives only one allele.

Question 2

A pea plant with genotype $$Pp ($$where $$P is $$dominant for purple flowers and $$p is $$recessive for white flowers) is self-pollinated. What is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$3$$ purple : $$1$$ white

Question 3

In a testcross between a pea plant with purple flowers of unknown genotype and a white-flowered plant, half the offspring have purple flowers and half have white flowers. What is the genotype of the purple-flowered parent?

Accepted Answer

Pp

Question 4

Which of the following scenarios illustrates the Law of Independent Assortment?

Accepted Answer

A plant with genotype $$YyRr$$ produces gametes $$YR$$, $$Yr$$, $$yR$$, and $$yr in $$equal proportions.

Question 5

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white flowers produces pink flowers.

Question 6

A person with genotype $$I^A I^B$$ for the ABO blood group will have which blood type?

Accepted Answer

Type AB

Question 7

Which of the following best describes pleiotropy?

Accepted Answer

One gene affects multiple phenotypic traits.

Question 8

In Labrador retrievers, coat color is determined by two genes: one gene determines pigment color ($$B$$ for black, $$b$$ for brown), and another gene determines whether pigment is deposited ($$E$$ for color, $$e$$ for no color). What is the phenotype of a dog with genotype $$Bb ee$$?

Accepted Answer

Yellow

Question 9

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

Accepted Answer

Height in humans

Question 10

A genetic counselor is advising a couple, both of whom are carriers for cystic fibrosis (autosomal recessive). What is the probability that their child will have cystic fibrosis?

Accepted Answer

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

Question 11

Which of the following best explains why Huntington’s disease persists in human populations despite being caused by a lethal dominant allele?

Accepted Answer

The disease only affects individuals after reproductive age.

Question 12

Which of the following is a multifactorial trait?

Accepted Answer

Hydrangea flower color, which depends on soil pH

Question 13

If a woman with blood type $$I^A i$$ and a man with blood type $$I^B i$$ have children, which blood types are possible among their offspring?

Accepted Answer

A, B, AB, and O

Question 14

Which of the following best describes codominance?

Accepted Answer

Both alleles are expressed in the heterozygote, resulting in a phenotype that shows both traits distinctly.

Question 15

A man with sickle-cell trait (heterozygous) marries a woman who is also heterozygous for the sickle-cell allele. What is the probability that their child will be homozygous for normal hemoglobin?

Accepted Answer

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

Question 16

Which of the following is true regarding the inheritance of recessively inherited disorders?

Accepted Answer

They only appear in individuals who are homozygous for the recessive allele.

Question 17

Which of the following best explains why consanguineous matings increase the risk of recessive genetic disorders?

Accepted Answer

Close relatives are more likely to carry the same rare recessive alleles.

Question 18

Which of the following is NOT a reason why Mendel chose pea plants for his experiments?

Accepted Answer

They have a long generation time.

Question 19

Which of the following best describes the difference between phenotype and genotype?

Accepted Answer

Phenotype is the physical appearance, while genotype is the genetic makeup.

Mendelian Genetics and Extensions: Principles of Inheritance

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