Question 1

Which of the following best explains why cloned animals, such as the first cloned sheep, often exhibit abnormal traits and shortened lifespans?

Accepted Answer

The cloning process disrupts the control of gene expression, leading to improper development.

Question 2

In prokaryotes, genes for related enzymes are often organized together in units called operons. What is the primary advantage of this arrangement?

Accepted Answer

It allows for simultaneous regulation of multiple genes in response to environmental changes.

Question 3

A mutation in E. coli impairs the ability of the lac repressor to bind to the lac operator. What is the most likely consequence for the cell?

Accepted Answer

The lac operon will be constitutively expressed, even in the absence of lactose.

Question 4

Why do nerve cells and skin cells in the same organism have different structures and functions, despite having identical genomes?

Accepted Answer

Different cell types selectively express different sets of genes.

Question 5

Which of the following is a direct result of DNA packing into nucleosomes and tight helical fibers?

Accepted Answer

Gene expression is blocked by preventing access of transcription proteins to DNA.

Question 6

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 and facilitate RNA polymerase attachment.

Question 7

Alternative RNA splicing allows a single gene to produce multiple types of mRNA. What is the molecular basis for this phenomenon?

Accepted Answer

Different combinations of exons are joined together after introns are removed.

Question 8

If the enzyme responsible for cleaving inactive insulin is deactivated, what will be the effect on insulin's form and function?

Accepted Answer

Insulin will remain inactive and unable to regulate blood glucose.

Question 9

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

Accepted Answer

miRNAs bind to mRNA molecules and either degrade them or block their translation.

Question 10

Homeotic genes are crucial in animal development because they:

Accepted Answer

Regulate groups of other genes that determine the anatomy of body parts.

Question 11

A DNA microarray is used in research to:

Accepted Answer

Determine which genes are turned on or off in a particular cell.

Question 12

In cell-to-cell signaling, what is the function of a signal transduction pathway?

Accepted Answer

It converts a signal on a target cell's surface to a specific response inside the cell.

Question 13

Plant cloning from differentiated cells demonstrates that differentiation is based on:

Accepted Answer

Control of gene expression rather than irreversible changes in the genome.

Question 14

Which statement correctly contrasts embryonic stem cells and adult stem cells?

Accepted Answer

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

Question 15

A mutation that converts a proto-oncogene into an oncogene can lead to cancer because:

Accepted Answer

The mutated gene causes cells to divide excessively.

Question 16

Why are epithelial cells more likely to become cancerous than other types of body cells?

Accepted Answer

They divide more frequently, increasing the chance of accumulating mutations.

Question 17

How does a cancer-causing mutation in a tumor-suppressor gene differ from the action of an oncogene?

Accepted Answer

A tumor-suppressor mutation removes inhibition of cell division, while an oncogene actively stimulates cell division.

Question 18

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 19

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

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 20

Which process allows a single human gene to produce more than 100,000 different peptides?

Accepted Answer

Alternative RNA splicing

Chapter 11: How Genes Are Controlled – Study Notes

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