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

$$\text{Product} \xrightarrow{\text{Inhibition}} \text{Enzyme 1}$$

Q: Which equation best represents the effect of histone acetylation on gene expression?

$$\text{Acetylation} \rightarrow \text{Loose Chromatin} \rightarrow \text{Increased Transcription}$$

Q: Which equation best represents alternative RNA splicing?

$$\text{Primary RNA Transcript} \rightarrow \text{mRNA}_1 + \text{mRNA}_2$$

Question 1

Which of the following best explains how two cells with the same set of genes can function differently, as seen in the eye of Anableps anableps ('four-eyed fish')?

Accepted Answer

Differential gene expression, regulated by specific transcription factors, allows cells to express different genes for specialized functions.

Question 2

In the trp operon of E. coli, what happens when tryptophan is present in high concentrations?

Accepted Answer

The repressor protein becomes active by binding tryptophan, shutting off transcription of the operon.

Question 3

Which equation represents feedback inhibition in a metabolic pathway?

Accepted Answer

$$	ext{Product} \xrightarrow{	ext{Inhibition}} 	ext{Enzyme 1}$$

Question 4

Which statement correctly distinguishes between repressible and inducible operons?

Accepted Answer

Repressible operons are usually on and can be shut off by a repressor; inducible operons are usually off and can be turned on by an inducer.

Question 5

Which of the following is a real-life example of negative gene regulation in bacteria?

Accepted Answer

The trp operon is turned off when tryptophan acts as a corepressor.

Question 6

Which equation best represents the effect of histone acetylation on gene expression?

Accepted Answer

$$	ext{Acetylation} ightarrow 	ext{Loose Chromatin} ightarrow 	ext{Increased Transcription}$$

Question 7

Epigenetic inheritance is best described as:

Accepted Answer

The inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence, such as chromatin modifications.

Question 8

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 bind to the promoter.

Question 9

A liver cell and a lens cell in humans contain the same DNA. What causes them to express different proteins?

Accepted Answer

Different combinations of available transcription activators bind to cell-specific enhancers.

Question 10

Which equation best represents alternative RNA splicing?

Accepted Answer

$$	ext{Primary RNA Transcript} ightarrow 	ext{mRNA}_1 + 	ext{mRNA}_2$$

Question 11

Which mechanism allows microRNAs (miRNAs) to regulate gene expression?

Accepted Answer

miRNAs bind to mRNA and either degrade it or block its translation.

Question 12

During embryonic development, what is the role of cytoplasmic determinants?

Accepted Answer

They are maternal substances in the egg that influence early development by causing differential gene expression in daughter cells.

Question 13

Which process irreversibly commits a cell to its final fate during differentiation?

Accepted Answer

Determination

Question 14

Which equation best represents the conversion of a proto-oncogene to an oncogene?

Accepted Answer

$$	ext{Proto-oncogene} \xrightarrow{	ext{Mutation/Amplification/Translocation}} 	ext{Oncogene}$$

Question 15

Which of the following is a function of the p53 tumor-suppressor gene?

Accepted Answer

It repairs damaged DNA and prevents cells from passing on mutations.

Question 16

Which scenario best illustrates the multistep model of cancer development?

Accepted Answer

Multiple mutations in oncogenes and tumor-suppressor genes accumulate over time, increasing cancer risk with age.

Question 17

Which equation best represents the effect of DNA methylation on gene expression?

Accepted Answer

$$	ext{DNA Methylation} ightarrow 	ext{Reduced Transcription}$$

Question 18

Which of the following is a real-world example of post-transcriptional regulation?

Accepted Answer

Alternative RNA splicing produces different troponin T proteins in muscle cells.

Question 19

Which mechanism allows viruses to contribute to cancer development?

Accepted Answer

Viruses can integrate into the host DNA and interfere with normal gene regulation.

Regulation of Gene Expression (Chapter 18): Mechanisms and Implications

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