Question 1

Which of the following best describes what occurs during the S phase of interphase in the cell cycle?

Accepted Answer

DNA is replicated, resulting in each chromosome consisting of two sister chromatids.

Question 2

A scientist is analyzing a pedigree for a rare genetic disorder. The disorder appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 3

Which of the following statements about polygenic traits is correct?

Accepted Answer

They result from the additive effects of multiple genes, often producing a continuous range of phenotypes.

Question 4

Which of the following best explains why gametes are haploid?

Accepted Answer

So that after fertilization, the resulting zygote has the correct diploid number of chromosomes.

Question 5

A woman is a carrier for an X-linked recessive disorder. If she has a child with a man who does not have the disorder, what is the probability that their son will have the disorder?

Accepted Answer

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

Question 6

Which of the following is NOT a step in the Polymerase Chain Reaction (PCR)?

Accepted Answer

Ligation

Question 7

Why are X-linked mutations more likely to be dominant in men than in women?

Accepted Answer

Men have only one X chromosome, so any mutation on it will be expressed.

Question 8

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each new DNA molecule consists of one parental strand and one newly synthesized strand.

Question 9

A population of beetles has the following genotype frequencies: $$AA = 0.36$$, $$Aa = 0.48$$, $$aa = 0.16. Is $$this population in Hardy-Weinberg equilibrium?

Accepted Answer

Yes, because $$p^2 = 0.36$, 2pq = 0.48$, q^2$ = 0.16.$$

Question 10

Which of the following is a reason why it is difficult to eliminate recessive alleles from a population?

Accepted Answer

Recessive alleles are hidden in heterozygotes and not subject to selection.

Question 11

Which of the following best describes the difference between incomplete dominance and codominance?

Accepted Answer

Incomplete dominance results in a blended phenotype, while codominance results in both phenotypes being expressed.

Question 12

Which of the following is NOT one of Darwin's four postulates of evolution by natural selection?

Accepted Answer

All individuals survive and reproduce equally.

Question 13

A researcher uses restriction enzymes and DNA ligase in a gene cloning experiment. What is the primary role of DNA ligase in this process?

Accepted Answer

To join together DNA fragments by forming phosphodiester bonds.

Question 14

Which of the following best explains why having different numbers of chromosomes can be harmful to an organism?

Accepted Answer

It leads to dosage compensation problems, disrupting gene expression balance.

Question 15

Which of the following is an example of artificial selection?

Accepted Answer

Humans breeding dogs for specific traits such as size or coat color.

Question 16

Which of the following is NOT a requirement for Hardy-Weinberg equilibrium?

Accepted Answer

Small population size

Question 17

A scientist is analyzing a gel electrophoresis result from a paternity test. The child shares several DNA bands with the mother and some with the alleged father. What does this indicate?

Accepted Answer

The child inherited DNA from both the mother and the alleged father, supporting paternity.

Question 18

Which of the following best describes the concept of parsimony in constructing evolutionary family trees?

Accepted Answer

The tree that requires the fewest evolutionary changes is preferred.

Question 19

Which of the following is a direct result of crossing over during meiosis?

Accepted Answer

Increased genetic variation among offspring

Question 20

Which of the following best explains why gene therapy on somatic cells does not affect future generations?

Accepted Answer

Somatic cells are not involved in reproduction, so changes are not passed to offspring.

Comprehensive Study Guide: Cell Division, Genetics, DNA, Evolution, and Biotechnology

Study Guide - Practice Questions

Study Guide - Flashcards