Question 1

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

Accepted Answer

Alleles for a trait separate during gamete formation, so each gamete carries only one allele for each gene.

Question 2

A pea plant with genotype $$Yy ($$yellow seeds) is crossed with a plant with genotype $$yy ($$green seeds). What is the expected phenotypic ratio of the offspring?

Accepted Answer

1 yellow : 1 green

Question 3

Which of the following is an example of codominance?

Accepted Answer

A person with type AB blood expresses both A and B antigens equally.

Question 4

If a woman who is a carrier for hemophilia (an X-linked recessive disorder) has children with a normal male, what is the probability that a son will have hemophilia?

Accepted Answer

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

Question 5

Which of the following best explains why siblings from the same parents can look different from each other?

Accepted Answer

Crossing over and independent assortment during meiosis create genetic variation.

Question 6

A test cross is performed between a yellow-seeded pea plant of unknown genotype and a green-seeded plant ($$yy). If $$any green-seeded offspring are produced, what was the genotype of the yellow-seeded parent?

Accepted Answer

$$Yy$$

Question 7

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

Accepted Answer

Human height

Question 8

In a dihybrid cross between two $$RrYy$$ pea plants, what is the expected phenotypic ratio for the offspring?

Accepted Answer

9:3:3:1

Question 9

Which of the following statements about dominant and recessive alleles is correct?

Accepted Answer

Dominant alleles are expressed in the phenotype if present, regardless of the other allele.

Question 10

A man with type O blood and a woman with type AB blood have children. Which blood types are possible for their children?

Accepted Answer

A and B only

Question 11

Which genetic principle explains why a person can inherit a gene for brown eyes from one parent and a gene for blue eyes from the other?

Accepted Answer

Law of Segregation

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 best describes pleiotropy?

Accepted Answer

A single gene affects multiple, seemingly unrelated traits.

Question 14

A woman with genotype $$X^N X^n ($$carrier for color blindness) and a man with genotype $$X^N Y$$ have a daughter. What is the probability that the daughter will be color blind?

Accepted Answer

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

Question 15

Which process increases genetic variation by exchanging segments between homologous chromosomes during meiosis?

Accepted Answer

Crossing over

Question 16

Which of the following is an example of incomplete dominance?

Accepted Answer

A red-flowered plant crossed with a white-flowered plant produces pink-flowered offspring.

Question 17

Which of the following best explains why males are more likely to express X-linked recessive disorders?

Accepted Answer

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

Question 18

Which of the following is NOT a feature of autosomal recessive inheritance?

Accepted Answer

All affected individuals must have an affected parent.

Question 19

A single gene mutation causes both anemia and resistance to malaria. This is an example of:

Accepted Answer

Pleiotropy

Question 20

Which of the following best describes the Law of Independent Assortment?

Accepted Answer

Alleles for different traits segregate independently during gamete formation.

Mendelian Genetics and Beyond: Study Notes for General Biology

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