Question 1

Which of the following best describes Mendel’s First Law (Law of Segregation)?

Accepted Answer

Each individual possesses two alleles for each gene, and these alleles segregate during gamete formation so that each gamete receives only one allele.

Question 2

A couple, both carriers for cystic fibrosis (an autosomal recessive disorder), are planning to have a child. What is the probability that their child will be affected by cystic fibrosis? Use a Punnett square to justify your answer.

Accepted Answer

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

Question 3

In a pedigree, a trait appears in every generation and affects both males and females equally. Which mode of inheritance is most likely?

Accepted Answer

Autosomal dominant

Question 4

During meiosis, at which stage does a cell become haploid?

Accepted Answer

After telophase II

Question 5

A plant with red flowers (RR) is crossed with a plant with white flowers (rr). The F1 generation has pink flowers (Rr). What type of inheritance is this an example of?

Accepted Answer

Incomplete dominance

Question 6

Which of the following best describes epistasis?

Accepted Answer

One gene masks the expression of another gene at a different locus.

Question 7

A woman is heterozygous for an X-linked recessive disorder. If she has a son, what is the probability that he will be affected?

Accepted Answer

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

Question 8

Which sex determination system is found in fruit flies (Drosophila melanogaster)?

Accepted Answer

Lygaeus system

Question 9

A cell with 2n = 6 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have after mitosis?

Accepted Answer

6

Question 10

If nondisjunction occurs during meiosis II, what is the expected outcome for the gametes?

Accepted Answer

Half of the gametes will be normal, one will have an extra chromosome, and one will lack a chromosome.

Question 11

Which chromosomal abnormality involves the exchange of segments between two non-homologous chromosomes without a change in the total amount of genetic material?

Accepted Answer

Reciprocal translocation

Question 12

A geneticist observes that two mutations in different genes produce the same phenotype. When crossed, the offspring have a wild-type phenotype. What does this result indicate?

Accepted Answer

The mutations complement each other.

Question 13

Which of the following best describes polyploidy?

Accepted Answer

An organism has multiple sets of chromosomes.

Question 14

A gene shows 80% penetrance. If 100 individuals have the genotype, how many are expected to express the phenotype?

Accepted Answer

80

Question 15

Which of the following is an example of genetic heterogeneity?

Accepted Answer

Mutations in different genes cause the same disease.

Question 16

In a branch diagram for a dihybrid cross ($$AaBb 	imes AaBb$$), what is the probability of obtaining an offspring with genotype $$AABB$$?

Accepted Answer

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

Question 17

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple traits.

Question 18

Which chromosomal abnormality is most likely to result in a loop structure during meiosis?

Accepted Answer

Inversion

Question 19

A male bird has the genotype ZZ, while a female bird has the genotype ZW. What type of sex determination system is this?

Accepted Answer

ZW system

Question 20

Which of the following best describes expressivity?

Accepted Answer

The degree to which a phenotype is expressed among individuals with the same genotype.

Genetics Exam Study Guide: Transmission, Chromosome Heredity, Gene Interaction, and Chromosome Abnormalities

Study Guide - Practice Questions

Study Guide - Flashcards