Question 1

Which of the following best describes the function of an operon in prokaryotic cells?

Accepted Answer

An operon is a unit of DNA containing a cluster of genes under the control of a single promoter and operator, allowing coordinated regulation.

Question 2

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

Accepted Answer

Lactose binds to the repressor, inactivating it and allowing RNA polymerase to transcribe the genes for lactose utilization.

Question 3

Which of the following is a key difference between the lac operon and the trp operon?

Accepted Answer

The lac operon is activated by the presence of lactose, while the trp operon is repressed by the presence of tryptophan.

Question 4

How does DNA packing affect gene expression in eukaryotic cells?

Accepted Answer

DNA packing blocks access of transcription proteins to DNA, generally reducing gene expression.

Question 5

Why do female cats display a tortoiseshell coat pattern, while male cats do not?

Accepted Answer

Female cats have two X chromosomes, and random X chromosome inactivation leads to patches of cells expressing different alleles for fur color.

Question 6

Which process allows a single gene to code for multiple proteins in eukaryotes?

Accepted Answer

Alternative RNA splicing

Question 7

A scientist wants to determine which genes are expressed in a specific tissue. Which technique should they use?

Accepted Answer

DNA microarray analysis

Question 8

Which of the following best describes the role of microRNAs (miRNAs) in gene regulation?

Accepted Answer

miRNAs bind to mRNA and either degrade it or block its translation, reducing gene expression.

Question 9

What is the primary goal of therapeutic cloning?

Accepted Answer

To produce embryonic stem cells for medical treatments.

Question 10

Which of the following statements about cancer is correct?

Accepted Answer

Cancer results from a series of genetic changes, including mutations in proto-oncogenes and tumor-suppressor genes.

Question 11

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

Accepted Answer

$$DNA \rightarrow RNA \rightarrow Protein$$

Question 12

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

Accepted Answer

The cell will divide uncontrollably, potentially leading to cancer.

Question 13

Which of the following is an example of epigenetic inheritance?

Accepted Answer

Chemical modification of histones that affects gene expression without changing the DNA sequence.

Question 14

In a signal transduction pathway, what is the role of relay proteins?

Accepted Answer

They transmit the signal from the receptor to the transcription factor inside the cell.

Question 15

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

Accepted Answer

Avoiding tobacco, eating a healthy diet, and exercising regularly.

Question 16

A researcher observes that a certain protein is only active after it is cleaved and folded into its final shape. Which regulatory mechanism is being described?

Accepted Answer

Regulation of gene expression at the level of protein activation.

Question 17

Which of the following best explains why differentiated plant cells can be used to clone an entire plant?

Accepted Answer

Differentiated plant cells retain all genetic information and are totipotent.

Question 18

Which of the following is a function of homeotic genes in animal development?

Accepted Answer

They regulate groups of other genes that determine the anatomy of body parts.

Question 19

Which of the following statements about tumor-suppressor genes is correct?

Accepted Answer

Mutations that inactivate tumor-suppressor genes can lead to uncontrolled cell division and cancer.

How Genes Are Controlled: Regulation of Gene Expression, Cloning, and the Genetic Basis of Cancer

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