Q: Which equation represents feedback inhibition in a metabolic pathway?

$$\text{Tryptophan} \xrightarrow{\text{inhibits}} \text{Enzyme 1}$$

Q: Which equation best represents the process of alternative RNA splicing?

$$\text{Primary RNA transcript} \rightarrow \text{mRNA with exons 1, 2, 3, 5}$$

Question 1

Which of the following best explains how two cells with the same genome can perform different functions, such as aerial and aquatic vision in a fish?

Accepted Answer

Differential gene expression, regulated by specific transcription factors, allows cells to express only the genes needed for their specialized function.

Question 2

In the trp operon, what happens when tryptophan levels are high in a bacterial cell?

Accepted Answer

Tryptophan acts as a corepressor, activating the repressor protein, which binds to the operator and shuts off transcription.

Question 3

Which equation represents feedback inhibition in a metabolic pathway?

Accepted Answer

$$	ext{Tryptophan} \xrightarrow{	ext{inhibits}} 	ext{Enzyme 1}$$

Question 4

Which of the following statements about the lac operon is correct?

Accepted Answer

The lac operon is an inducible operon that is usually off and is turned on by the presence of allolactose.

Question 5

Which of the following best describes the effect of histone acetylation on gene expression?

Accepted Answer

Histone acetylation loosens chromatin structure, enhancing transcription.

Question 6

DNA methylation is most likely to result in which of the following outcomes?

Accepted Answer

Reduced transcription of methylated genes.

Question 7

Which of the following is an example of epigenetic inheritance?

Accepted Answer

DNA methylation patterns passed to future generations of cells without altering the DNA sequence.

Question 8

Which equation best represents the process of alternative RNA splicing?

Accepted Answer

$$	ext{Primary RNA transcript} ightarrow 	ext{mRNA with exons 1, 2, 3, 5}$$

Question 9

Which of the following mechanisms allows a cell to rapidly adjust gene expression in response to environmental changes?

Accepted Answer

Post-transcriptional regulation, such as mRNA degradation and translation initiation control.

Question 10

What is the role of ubiquitin in protein regulation?

Accepted Answer

Ubiquitin marks proteins for degradation by proteasomes.

Question 11

Which of the following best describes combinatorial control of gene activation in eukaryotes?

Accepted Answer

A particular combination of control elements can activate transcription only when the appropriate activator proteins are present.

Question 12

Which equation represents the effect of cAMP on the lac operon when glucose is scarce?

Accepted Answer

$$	ext{cAMP} + 	ext{CRP} ightarrow 	ext{Active CRP}$$

Question 13

Which of the following is true about the life span of mRNA in eukaryotic cells?

Accepted Answer

The length of the poly-A tail influences the life span of mRNA in eukaryotes.

Question 14

Which of the following is a function of general transcription factors in eukaryotic gene expression?

Accepted Answer

They are essential for the transcription of all protein-coding genes by helping RNA polymerase initiate transcription.

Question 15

Which of the following best describes the function of an operator in a bacterial operon?

Accepted Answer

It is a segment of DNA that acts as an 'on-off switch' for gene expression by binding repressor proteins.

Question 16

Which of the following scenarios illustrates negative gene regulation?

Accepted Answer

A repressor protein binds to the operator, shutting off transcription.

Question 17

Which of the following is a real-world example of coordinate regulation in eukaryotic cells?

Accepted Answer

The expression of liver-specific genes is controlled by liver-specific enhancers and activators.

Question 18

Which equation best represents the process of protein degradation in cells?

Accepted Answer

$$	ext{Protein} + 	ext{Ubiquitin} ightarrow 	ext{Ubiquitinated protein} \xrightarrow{	ext{Proteasome}} 	ext{Amino acids}$$

Question 19

Which of the following statements about enhancers is correct?

Accepted Answer

Enhancers are distal control elements that may be far from the gene or located in an intron, and they bind specific transcription factors to regulate transcription.

Regulation of Gene Expression: Mechanisms and Control in Prokaryotes and Eukaryotes

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