Question 1

Which of the following statements best describes Mendel's principle of segregation?

Accepted Answer

Each parent contributes only one allele for each gene to their offspring, and these alleles separate during gamete formation.

Question 2

A plant with genotype $$YyRr is $$self-crossed. What is the probability that an offspring will have yellow, wrinkled seeds? (Yellow is dominant to green, round is dominant to wrinkled.)

Accepted Answer

$$\frac{3}{16}$$

Question 3

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white flowers produces pink flowers.

Question 4

In a testcross, a pea plant with an unknown genotype but dominant phenotype is crossed with a homozygous recessive plant. If all offspring show the dominant phenotype, what is the genotype of the unknown parent?

Accepted Answer

Homozygous dominant

Question 5

Which of the following best explains why more males than females are affected by X-linked recessive disorders?

Accepted Answer

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

Question 6

A woman with normal vision has a son who is red-green colorblind. Which of the following must be true?

Accepted Answer

She is a carrier for the colorblind allele.

Question 7

Which of the following is an example of pleiotropy?

Accepted Answer

A single gene mutation causes both sickle-shaped red blood cells and resistance to malaria.

Question 8

If a person with type A blood receives a transfusion of type B blood, what is the most likely outcome?

Accepted Answer

Agglutination and hemolysis of the donated red blood cells.

Question 9

Which of the following inheritance patterns is characterized by the trait often skipping generations and affecting both males and females equally?

Accepted Answer

Autosomal recessive

Question 10

A cross between KkLlMm x KkLlMm is performed. What fraction of the offspring will be homozygous recessive for all three genes (kkllmm)?

Accepted Answer

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

Question 11

Which of the following best describes codominance?

Accepted Answer

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

Question 12

Which of the following is a real-world example of a polygenic trait?

Accepted Answer

Human skin color

Question 13

Which of the following statements about dominant alleles is correct?

Accepted Answer

Dominant alleles are not necessarily more common or better adapted than recessive alleles.

Question 14

Which of the following mechanisms explains why mitochondrial genetic disorders are inherited only from the mother?

Accepted Answer

Sperm mitochondria are typically lost during fertilization.

Question 15

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 16

Which of the following best describes the principle of independent assortment?

Accepted Answer

Alleles of different genes assort independently of one another during gamete formation.

Question 17

Which of the following is an example of gene-by-gene interaction (epistasis)?

Accepted Answer

Labrador retriever coat color, where one gene affects pigment production and another affects pigment deposition.

Question 18

Which of the following is a key reason why studying human genetics is more challenging than studying genetics in pea plants?

Accepted Answer

Humans have fewer offspring and controlled breeding is unethical.

Question 19

A woman with genotype $$X^R X^r ($$where $$X^R is $$the normal vision allele and $$X^r is $$the red-green colorblindness allele) marries a man with normal vision ($$X^R Y). $$What is the probability that their son will be colorblind?

Accepted Answer

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

Question 20

Which of the following best describes a multifactorial trait?

Accepted Answer

A trait influenced by multiple genes and environmental factors.

Mendelian and Non-Mendelian Genetics: Principles, Patterns, and Extensions

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