Question 1

Which of the following best describes 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

In a cross between two heterozygous pea plants (Pp x Pp), what is the expected genotypic ratio in the F2 generation?

Accepted Answer

$$1:2:1 (PP$$:Pp:pp)

Question 3

A testcross is performed between a pea plant with purple flowers of unknown genotype and a white-flowered plant. If half the offspring 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

Alleles for seed color and seed shape are inherited independently in a dihybrid cross.

Question 5

If a plant with genotype YyRr is crossed with another YyRr plant, what is the probability that an offspring will have the genotype yyrr?

Accepted Answer

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

Question 6

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white snapdragons produces pink offspring.

Question 7

Which genotype would result in blood type AB in humans?

Accepted Answer

$$I^A I^B$$

Question 8

A man with genotype AaBbCc marries a woman with the same genotype. Assuming independent assortment, what is the probability that their child will be homozygous recessive for all three genes?

Accepted Answer

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

Question 9

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple phenotypic traits.

Question 10

In Labrador retrievers, coat color is determined by two genes. If a black lab (BbEe) is crossed with a chocolate lab (bbEe), what is the probability of producing a yellow lab (ee)?

Accepted Answer

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

Question 11

Which of the following is an example of polygenic inheritance?

Accepted Answer

Human skin color

Question 12

A pedigree shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 13

Which of the following statements about sickle-cell disease is correct?

Accepted Answer

Heterozygotes are less susceptible to malaria.

Question 14

Which rule would you use to calculate the probability that an offspring from a monohybrid cross is either homozygous dominant or heterozygous?

Accepted Answer

Addition rule

Question 15

Which of the following is a multifactorial trait?

Accepted Answer

Heart disease

Question 16

If two carriers of a recessive genetic disorder (Aa x Aa) have a child, what is the probability that the child will be affected?

Accepted Answer

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

Question 17

Which of the following best explains why dominant alleles are not necessarily more common in a population than recessive alleles?

Accepted Answer

Allele frequency is determined by evolutionary factors, not dominance.

Question 18

Which of the following is true about Huntington’s disease?

Accepted Answer

It is caused by a dominant allele and symptoms appear later in life.

Question 19

Which of the following best describes codominance?

Accepted Answer

Both alleles are fully expressed in the phenotype of the heterozygote.

Question 20

Which of the following is a consequence of consanguineous matings?

Accepted Answer

Increased likelihood of homozygosity for rare recessive alleles.

Mendel and the Gene Idea: Principles of Inheritance

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