Question 1

Which of the following best describes the role of negative feedback inhibition in cellular gene expression?

Accepted Answer

It reduces the activity of a pathway when its end product accumulates, maintaining homeostasis.

Question 2

In the context of the lac operon in E. coli, what is the function of the repressor protein?

Accepted Answer

It binds to the operator to block RNA polymerase from transcribing the operon.

Question 3

Which of the following equations best represents the relationship between the rate of gene expression ($$R) $$and the concentration of a repressor protein ($$[Repressor]) in a $$simple negative feedback system?

Accepted Answer

$$R = \frac{k}{1 + [Repressor]}$$

Question 4

A mutation causes the operator region of an operon to be deleted. What is the most likely consequence for gene expression?

Accepted Answer

Gene expression will be constitutively active, regardless of repressor presence.

Question 5

Which process is directly responsible for transporting mRNA from the nucleus to the cytoplasm in eukaryotic cells?

Accepted Answer

Nuclear export

Question 6

A patient is diagnosed with a genetic disorder that impairs protein transport within the cell. Which cellular process is most likely to be affected as a result?

Accepted Answer

Localization of proteins to their functional destinations

Question 7

Which of the following best explains how chromatin structure can regulate gene expression?

Accepted Answer

Condensed chromatin (heterochromatin) restricts access to transcription machinery, reducing gene expression.

Question 8

Which step in gene expression is most directly affected by alternative splicing?

Accepted Answer

RNA processing

Question 9

If a cell experiences a sudden increase in temperature, which regulatory mechanism is most likely to be activated to protect gene expression?

Accepted Answer

Upregulation of heat shock proteins via transcriptional activation.

Question 10

Which of the following scenarios best illustrates positive feedback in gene regulation?

Accepted Answer

A gene product activates the transcription of its own gene, increasing its concentration.

Question 11

In a multi-step gene regulation pathway, which sequence correctly represents the flow of genetic information?

Accepted Answer

DNA $$\rightarrow$$ RNA $$\rightarrow$$ Protein

Question 12

A scientist discovers a new operon in bacteria that is only active in the presence of a specific sugar. Which type of operon is this most likely to be?

Accepted Answer

Inducible operon

Question 13

Which of the following is NOT a direct way that changes in gene expression can influence cell function?

Accepted Answer

Changing the sequence of DNA in the genome

Question 14

Which equation best models the effect of an activator protein ($$[Activator]) on $$the rate of transcription ($$T) in a $$simplified system?

Accepted Answer

$$T = k 	imes [Activator]$$

Question 15

Which of the following best describes the role of RNA processing in eukaryotic gene expression?

Accepted Answer

It removes introns and adds a 5' cap and poly-A tail to pre-mRNA.

Question 16

A cell is exposed to a drug that inhibits transcription. Which process will be directly affected first?

Accepted Answer

Synthesis of mRNA from DNA

Question 17

Which of the following is a consequence of a mutation that prevents the binding of a repressor protein to the operator in an operon?

Accepted Answer

The operon will be constitutively expressed.

Question 18

Which of the following is a real-world example of gene regulation affecting human health?

Accepted Answer

Lactose intolerance due to lack of lactase gene expression in adults.

Question 19

Which process is most directly responsible for the removal of introns from pre-mRNA?

Accepted Answer

Splicing

Question 20

A researcher finds that a certain gene is only expressed when a specific transcription factor is present. What does this suggest about the regulation of this gene?

Accepted Answer

The gene is regulated by an activator protein.

Regulation of Gene Expression: Study Guide Notes

Guida di studio - Domande di pratica

Study guide - Flashcard