Q: Which of the following equations best represents the relationship between gene expression and protein synthesis?

$$\text{Gene Expression} = \text{Transcription} + \text{Translation}$$

Question 1

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

Accepted Answer

It acts as a switch that controls the access of RNA polymerase to the structural genes.

Question 2

In the lac operon, what happens when lactose is present in the environment?

Accepted Answer

Lactose binds to the repressor, inactivating it and allowing transcription of the structural genes.

Question 3

Which of the following equations best represents the relationship between gene expression and protein synthesis?

Accepted Answer

$$	ext{Gene Expression} = 	ext{Transcription} + 	ext{Translation}$$

Question 4

A mutation in the enhancer region of the lactase gene leads to lactose tolerance in adults. Why does this mutation affect gene expression?

Accepted Answer

It alters the binding of transcription factors, increasing transcription of the lactase gene.

Question 5

Which of the following statements about inducible operons is correct?

Accepted Answer

They are turned on only in the presence of a specific inducer molecule.

Question 6

In the trp operon, what is the role of tryptophan?

Accepted Answer

It acts as a corepressor, activating the repressor to turn the operon off.

Question 7

Which of the following best explains why bacteria do not constantly produce all proteins at all times?

Accepted Answer

Producing all proteins at all times would waste energy and resources.

Question 8

A student is studying a bacterial operon that is normally 'on' but can be turned 'off' when a specific molecule is present. Which type of operon is this?

Accepted Answer

Repressible operon

Question 9

Which of the following is the correct sequence of elements in a typical prokaryotic operon?

Accepted Answer

Regulatory Gene, Promoter, Operator, Structural Genes

Question 10

If a mutation causes the repressor protein of the lac operon to be unable to bind lactose, what would be the likely outcome?

Accepted Answer

The operon would be permanently turned off, even if lactose is present.

Question 11

Which type of epigenetic tag would you expect to increase around the lactase gene in lactose-intolerant adults?

Accepted Answer

DNA methylation

Question 12

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

Accepted Answer

On, unless tryptophan is present

Question 13

A scientist adds a molecule that mimics lactose to a culture of E. coli. What is the most likely effect on the lac operon?

Accepted Answer

The operon will turn on because the mimic inactivates the repressor.

Question 14

Which of the following scenarios best illustrates negative feedback regulation in prokaryotic gene expression?

Accepted Answer

The presence of tryptophan turns off the trp operon, stopping further tryptophan synthesis.

Question 15

Which of the following is a direct result of RNA polymerase binding to the promoter region of an operon?

Accepted Answer

Transcription of the structural genes begins.

Question 16

Which of the following best explains why eye cells do not produce insulin?

Accepted Answer

The insulin gene is present but not expressed due to gene regulation.

Question 17

A mutation causes the operator of the lac operon to be permanently bound by the repressor, regardless of lactose presence. What is the most likely outcome?

Accepted Answer

Lactase will never be produced, even if lactose is present.

Question 18

Which of the following best describes the difference between inducible and repressible operons?

Accepted Answer

Inducible operons are off until an inducer turns them on; repressible operons are on until a corepressor turns them off.

Gene Regulation in Prokaryotes: Operons, Inducible and Repressible Systems

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