Question 1

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

Accepted Answer

Gene regulation allows different sets of genes to be expressed in different cell types.

Question 2

In the lac operon of E. coli, what would be the most likely consequence if a mutation prevented the repressor protein from binding to the operator?

Accepted Answer

The genes for lactose digestion would be expressed continuously, even in the absence of lactose.

Question 3

Which of the following is a key difference between gene regulation in prokaryotes and eukaryotes?

Accepted Answer

Prokaryotes use operons, while eukaryotes regulate genes at multiple levels including DNA packing and RNA processing.

Question 4

Which of the following best describes the role of transcription factors in eukaryotic gene regulation?

Accepted Answer

They bind to enhancers and promoters to help initiate transcription.

Question 5

A female cat displays a tortoiseshell pattern due to X chromosome inactivation. Which of the following statements best explains this phenomenon?

Accepted Answer

One X chromosome is randomly inactivated in each cell early in development, leading to patches of cells expressing different alleles.

Question 6

Alternative RNA splicing allows a single gene to:

Accepted Answer

Produce multiple types of polypeptides by splicing exons in different ways.

Question 7

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

Accepted Answer

They bind to complementary mRNA sequences and block translation or promote mRNA degradation.

Question 8

A signal molecule binds to a receptor on the surface of a target cell and triggers a signal transduction pathway. What is the most likely result of this process?

Accepted Answer

The target cell alters gene expression without the signal molecule entering the cell.

Question 9

Homeotic genes are important in animal development because they:

Accepted Answer

Regulate groups of other genes that determine the formation of body parts in specific locations.

Question 10

Which of the following statements about reproductive cloning in mammals is correct?

Accepted Answer

It involves replacing the nucleus of an egg cell with the nucleus from an adult body cell.

Question 11

Which of the following is a potential disadvantage of using reproductive cloning to conserve endangered species?

Accepted Answer

Cloning does not increase genetic diversity in the population.

Question 12

Which of the following best describes the difference between embryonic stem cells and adult stem cells?

Accepted Answer

Embryonic stem cells can develop into a wider variety of specialized cells than adult stem cells.

Question 13

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

Accepted Answer

They encode proteins that inhibit cell division and prevent uncontrolled cell growth.

Question 14

A proto-oncogene can become an oncogene through which of the following mechanisms?

Accepted Answer

A mutation that leads to excessive or uncontrolled expression of the gene.

Question 15

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

Accepted Answer

Tobacco use

Question 16

Which of the following dietary choices is associated with a reduced risk of cancer?

Accepted Answer

Eating 20–30 grams of plant fiber daily

Question 17

Which equation best represents the central dogma of molecular biology?

Accepted Answer

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

Question 18

A scientist uses a DNA microarray to compare gene expression in healthy and cancerous tissue. What does a yellow spot on the microarray indicate?

Accepted Answer

The gene is expressed in both healthy and cancerous tissue.

Question 19

Which of the following best explains why cloned animals often have more health problems than animals produced by sexual reproduction?

Accepted Answer

Cloned animals may have abnormal gene expression due to incomplete reprogramming of the donor nucleus.

Question 20

Which of the following is a real-world application of therapeutic cloning?

Accepted Answer

Producing embryonic stem cells for potential treatment of diseases or organ repair.

How Genes Are Controlled: Regulation of Gene Expression in Prokaryotes and Eukaryotes

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