Question 1

Which of the following best describes gene regulation in multicellular organisms?

Accepted Answer

Gene regulation allows cells with identical DNA to specialize by turning certain genes on or off.

Question 2

What is the role of the operator in the lac operon of E. coli?

Accepted Answer

It acts as a switch that controls whether the genes for lactose metabolism are transcribed.

Question 3

A mutation in a homeotic gene during embryonic development is most likely to result in:

Accepted Answer

Abnormal placement or development of body parts.

Question 4

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

Accepted Answer

$$DNA \rightarrow mRNA \rightarrow Protein$$

Question 5

Why is alternative RNA splicing important in eukaryotic cells?

Accepted Answer

It allows a single gene to produce multiple types of polypeptides.

Question 6

Which of the following is a function of microRNAs (miRNAs) in gene regulation?

Accepted Answer

They bind to mRNA and can block translation or cause mRNA degradation.

Question 7

In the context of cancer, what is the difference between a proto-oncogene and an oncogene?

Accepted Answer

A proto-oncogene is a normal gene that can become an oncogene through mutation.

Question 8

Which of the following best explains X chromosome inactivation in female mammals?

Accepted Answer

One X chromosome is randomly inactivated in each cell early in development, leading to mosaic gene expression.

Question 9

What is the primary function of tumor-suppressor genes?

Accepted Answer

To prevent uncontrolled cell growth.

Question 10

Which of the following is a real-world application of DNA microarrays?

Accepted Answer

Determining which genes are active in different tissues to optimize cancer therapy.

Question 11

In the lac operon, what happens when lactose is present?

Accepted Answer

The repressor is inactivated, allowing RNA polymerase to transcribe the genes for lactose metabolism.

Question 12

Which process allows a cell to adjust the kinds and amounts of its proteins after translation?

Accepted Answer

Selective breakdown of proteins.

Question 13

What is the main difference between reproductive cloning and therapeutic cloning?

Accepted Answer

Reproductive cloning produces a living organism, while therapeutic cloning produces stem cells for medical use.

Question 14

Which of the following behaviors is most strongly associated with increased cancer risk?

Accepted Answer

Tobacco use.

Question 15

What is the role of transcription factors in eukaryotic gene regulation?

Accepted Answer

They bind to enhancers and the promoter to help RNA polymerase initiate transcription.

Question 16

Which of the following is a plausible consequence of cloning endangered animals?

Accepted Answer

It may reduce genetic diversity in the population.

Question 17

Which equation represents the process of alternative RNA splicing?

Accepted Answer

$$	ext{Pre-mRNA} ightarrow 	ext{mRNA}_1 or$$ $$	ext{mRNA}_2$$

Question 18

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

Accepted Answer

Adult stem cells can give rise to only a few related types of specialized cells.

Question 19

What is the function of a signal transduction pathway in cell signaling?

Accepted Answer

It converts a signal received outside a cell to a specific response inside the target cell.

Question 20

Which of the following statements about cancer is correct?

Accepted Answer

Cancer is caused by uncontrolled cell growth due to changes in gene expression.

Chapter 11: How Genes Are Controlled

Study Guide - Practice Questions