Q: Which equation represents the process of transcription?

$$\text{DNA} \rightarrow \text{mRNA}$$

Q: Which equation best represents the process of translation?

$$\text{mRNA} \rightarrow \text{Protein}$$

Question 1

Why is it advantageous for bacteria to regulate the expression of their genes?

Accepted Answer

Because it allows them to conserve energy and resources by only producing proteins when needed.

Question 2

In the lac operon of E. coli, what happens when lactose is present?

Accepted Answer

The repressor is inactivated, allowing RNA polymerase to transcribe the operon genes.

Question 3

Which of the following best describes a repressible operon?

Accepted Answer

An operon that is usually on but can be turned off when a specific molecule is present.

Question 4

Which equation represents the process of transcription?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{mRNA}$$

Question 5

A mutation disables the operator region of the trp operon in E. coli. What is the most likely result?

Accepted Answer

The operon will be constitutively expressed, regardless of tryptophan levels.

Question 6

Which of the following is a post-transcriptional modification in eukaryotes?

Accepted Answer

Addition of a poly-A tail to mRNA

Question 7

What is the role of alternative splicing in eukaryotic gene regulation?

Accepted Answer

It allows a single gene to produce multiple protein variants.

Question 8

Which of the following mechanisms can block translation of mRNA in eukaryotes?

Accepted Answer

Binding of miRNA or siRNA to mRNA

Question 9

Which equation best represents the process of translation?

Accepted Answer

$$	ext{mRNA} ightarrow 	ext{Protein}$$

Question 10

A cell has a mutation that prevents the addition of a poly-A tail to its mRNA. What is the most likely consequence?

Accepted Answer

The mRNA will be rapidly degraded and not efficiently translated.

Question 11

Which of the following is a function of regulatory proteins binding to the 5' untranslated region (UTR) of mRNA?

Accepted Answer

They can inhibit or enhance translation of the mRNA.

Question 12

What is the primary function of the trp operon in E. coli?

Accepted Answer

To regulate the synthesis of tryptophan in response to its availability.

Question 13

Which process is most directly affected by DNA methylation in eukaryotes?

Accepted Answer

Transcriptional initiation

Question 14

A scientist discovers a eukaryotic gene that produces several different proteins from the same DNA sequence. Which mechanism is most likely responsible?

Accepted Answer

Alternative splicing

Question 15

Which of the following is NOT a level at which eukaryotic gene expression can be regulated?

Accepted Answer

Replication of DNA

Question 16

Which equation represents the effect of a repressor binding to the operator in a prokaryotic operon?

Accepted Answer

$$	ext{Repressor} + 	ext{Operator} ightarrow 	ext{Transcription Blocked}$$

Question 17

Which of the following best explains the role of ubiquitin in post-translational control?

Accepted Answer

It tags proteins for degradation by the proteasome.

Question 18

A mutation causes a eukaryotic cell to lose all miRNA production. What is the most likely effect?

Accepted Answer

Many mRNAs will be translated that should have been silenced.

Question 19

Which of the following is a real-world example of gene regulation at the translational level?

Accepted Answer

Ferritin mRNA translation is blocked in the absence of iron in human cells.

Question 20

Epigenetics is best defined as:

Accepted Answer

The study of heritable changes in gene function that do not involve changes in the DNA sequence.

Regulation of Gene Activity: Prokaryotic and Eukaryotic Mechanisms

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