Question 1

Which of the following best explains why nerve cells and skin cells in the same individual can have very different structures and functions, even though they contain the same DNA?

Accepted Answer

Nerve cells and skin cells express different genes due to selective gene expression.

Question 2

In prokaryotes, what is the primary mechanism by which genes for related enzymes are regulated together?

Accepted Answer

By grouping genes into operons controlled by regulatory proteins.

Question 3

Which of the following is a direct result of DNA packing in eukaryotic chromosomes?

Accepted Answer

Blocking gene expression by preventing access of transcription proteins to DNA.

Question 4

What must occur before RNA polymerase can bind to a promoter and transcribe a specific eukaryotic gene?

Accepted Answer

Transcription factors must bind to the DNA.

Question 5

Alternative RNA splicing allows a single gene to:

Accepted Answer

Produce multiple types of mRNA and thus different proteins.

Question 6

Which of the following best describes the role of noncoding RNAs in gene expression?

Accepted Answer

They can prevent gene expression by degrading mRNA or blocking translation.

Question 7

A scientist uses nucleic acid hybridization to study gene expression. What is the scientist most likely trying to determine?

Accepted Answer

Which genes are turned on or off in a particular cell.

Question 8

Which of the following is an example of epigenetic inheritance?

Accepted Answer

Chemical modification of DNA bases or histone proteins that affects gene expression.

Question 9

In the context of cell signaling, what is a signal transduction pathway?

Accepted Answer

A series of molecular changes that converts a signal on a cell’s surface to a specific response inside the cell.

Question 10

Which of the following statements about plant cloning is supported by experimental evidence?

Accepted Answer

Differentiated plant cells retain all their genetic potential and can give rise to a whole plant.

Question 11

Which of the following best describes the difference between reproductive cloning and therapeutic cloning in mammals?

Accepted Answer

Reproductive cloning produces a new individual, while therapeutic cloning produces embryonic stem cells for medical use.

Question 12

Which of the following is true about embryonic stem cells compared to adult stem cells?

Accepted Answer

Embryonic stem cells can give rise to all cell types, while adult stem cells are usually limited to certain cell types.

Question 13

A mutation converts a proto-oncogene into an oncogene. What is the likely result?

Accepted Answer

The cell will divide excessively, potentially leading to cancer.

Question 14

Which of the following best explains why epithelial cells are more likely to become cancerous than other cell types?

Accepted Answer

Epithelial cells divide more frequently, increasing the chance of accumulating mutations.

Question 15

Which of the following is a function of tumor-suppressor genes?

Accepted Answer

They help prevent uncontrolled cell division.

Question 16

Which of the following lifestyle choices can help reduce the risk of developing cancer?

Accepted Answer

Reducing exposure to carcinogens and making healthy lifestyle choices.

Question 17

A faulty protein in a signal transduction pathway can lead to cancer by:

Accepted Answer

Disrupting the regulation of the cell cycle, leading to uncontrolled cell division.

Question 18

Which of the following equations best represents the flow of genetic information in gene expression?

Accepted Answer

$$DNA \rightarrow RNA \rightarrow Protein$$

Question 19

Which of the following is a real-world example of gene regulation in response to environmental changes in prokaryotes?

Accepted Answer

The lac operon in E. coli turning on in the presence of lactose.

Question 20

A researcher finds that a certain mRNA is degraded quickly in the cytoplasm. What is the likely effect on protein production from this gene?

Accepted Answer

Protein production will decrease due to the shorter lifetime of the mRNA.

How Genes Are Controlled: Regulation, Cloning, and Cancer

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