Q: Which of the following equations best represents the feedback inhibition mechanism in the trp operon pathway?

$$\text{Tryptophan} + \text{Inactive Repressor} \rightarrow \text{Active Repressor}$$

Question 1

Which of the following best describes the function of the trp operon in E. coli?

Accepted Answer

It is a repressible operon that is turned off when tryptophan is present.

Question 2

What is the role of the repressor protein in the lac operon when lactose is absent?

Accepted Answer

The repressor binds to the operator, preventing RNA polymerase from transcribing the genes.

Question 3

Which of the following is a direct result of DNA methylation in eukaryotic cells?

Accepted Answer

Decreased transcription of the methylated gene.

Question 4

A scientist inserts a gene from a firefly into a tobacco plant, resulting in the plant glowing in the dark. What is this an example of?

Accepted Answer

Transgenic organism

Question 5

Which of the following best explains why cells do not express all their genes all the time?

Accepted Answer

It would waste energy and resources to produce unnecessary proteins.

Question 6

In the context of the lac operon, what is the function of allolactose?

Accepted Answer

It acts as an inducer, inactivating the repressor protein.

Question 7

Which of the following steps in gene expression regulation is unique to eukaryotes and not found in prokaryotes?

Accepted Answer

RNA splicing to remove introns.

Question 8

A patient receives a genetically modified pig heart with three immune-rejection-related genes knocked down and six human genes inserted. What is the primary goal of these genetic modifications?

Accepted Answer

To reduce immune rejection and improve compatibility with the human recipient.

Question 9

Which of the following best describes differential splicing in eukaryotic cells?

Accepted Answer

The process by which different exons are joined to produce multiple mRNA variants from a single gene.

Question 10

Which of the following equations best represents the feedback inhibition mechanism in the trp operon pathway?

Accepted Answer

$$	ext{Tryptophan} + 	ext{Inactive Repressor} ightarrow 	ext{Active Repressor}$$

Question 11

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

Accepted Answer

DNA methylation patterns linking childhood hardship to depression.

Question 12

Which of the following is the correct sequence of events for gene expression in eukaryotic cells?

Accepted Answer

DNA → Transcription → RNA processing → Translation → Protein

Question 13

Which of the following best explains why the lac operon is considered an inducible operon?

Accepted Answer

It is turned on in the presence of an inducer (lactose).

Question 14

Which of the following is NOT a step where gene expression can be regulated in eukaryotic cells?

Accepted Answer

DNA replication

Question 15

A restriction enzyme cuts a plasmid and a gene of interest, which are then joined together. What enzyme is used to seal the DNA fragments?

Accepted Answer

DNA ligase

Question 16

Which of the following best describes the function of enhancer sequences in eukaryotic gene regulation?

Accepted Answer

They increase the rate of transcription when bound by activators.

Question 17

Which of the following scenarios best illustrates the application of recombinant DNA technology?

Accepted Answer

A patient receives insulin produced by genetically engineered bacteria.

Question 18

Which of the following is a plausible consequence of knocking down immune-rejection-related genes in a pig heart before transplantation into a human?

Accepted Answer

The pig heart is more likely to be accepted by the human immune system.

Question 19

Which of the following best describes feedback inhibition in the context of the trp operon?

Accepted Answer

Tryptophan binds to the repressor, activating it and shutting down its own synthesis.

Question 20

Which of the following is a correct statement about the regulation of gene expression in prokaryotes versus eukaryotes?

Accepted Answer

Prokaryotes often use operons to regulate multiple genes together, while eukaryotes regulate genes individually at multiple levels.

Regulation of Gene Expression and Biotechnology

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