Q: Which of the following equations correctly represents the directionality of transcription?

$$\text{DNA (3' \rightarrow 5')} \rightarrow \text{RNA (5' \rightarrow 3')}$$

Q: Which equation represents the addition of a poly(A) tail to eukaryotic mRNA?

$$\text{pre-mRNA} + \text{poly(A) polymerase} \rightarrow \text{mRNA with poly(A) tail}$$

Q: Which equation best represents the process of transcription in prokaryotes?

$$\text{DNA} + \text{RNA polymerase holoenzyme} \rightarrow \text{mRNA}$$

Question 1

Which statement best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

In prokaryotic transcription, what is the primary function of the sigma factor ($$\sigma) in $$the RNA polymerase holoenzyme?

Accepted Answer

It recognizes and binds to the promoter consensus sequences, enabling transcription initiation.

Question 3

Which of the following equations correctly represents the directionality of transcription?

Accepted Answer

$$	ext{DNA (3' ightarrow 5')} ightarrow 	ext{RNA (5' ightarrow 3')}$$

Question 4

Which event must first occur before a eukaryotic protein-coding gene is transcribed?

Accepted Answer

Sequence-specific binding of a transcription factor to the promoter.

Question 5

A prokaryotic gene contains a consensus -35 and -10 promoter element. What is the typical spacing between these elements?

Accepted Answer

$$\sim 17$$ base pairs

Question 6

Which mechanism is responsible for the termination of transcription in prokaryotes that involves a hairpin loop and a U-rich sequence?

Accepted Answer

Rho-independent termination

Question 7

In eukaryotes, what is the function of the 5' cap added to mRNA?

Accepted Answer

It facilitates binding to the ribosome and protects mRNA from ribonucleases.

Question 8

Suppose the DNA of a gene contains five regions—A, B, C, D, and E, in that order. Regions A, B, and D are located in introns, while regions C and E are located in exons. What is the order of the regions in the mature mRNA transcribed from that sequence?

Accepted Answer

CE

Question 9

Which of the following statements best explains why prokaryotic mRNA is co-linear with its DNA template?

Accepted Answer

Prokaryotic genes lack introns, so the mRNA is a direct copy of the DNA coding sequence.

Question 10

Which equation represents the addition of a poly(A) tail to eukaryotic mRNA?

Accepted Answer

$$	ext{pre-mRNA} + 	ext{poly(A) polymerase} ightarrow 	ext{mRNA with poly(A) tail}$$

Question 11

Which of the following is NOT a function of the CTD (C-terminal domain) of RNA polymerase II in eukaryotes?

Accepted Answer

Catalyzing the formation of phosphodiester bonds during transcription

Question 12

Which of the following statements about alternative splicing is correct?

Accepted Answer

Alternative splicing allows a single gene to produce multiple protein products.

Question 13

Which equation best represents the process of transcription in prokaryotes?

Accepted Answer

$$	ext{DNA} + 	ext{RNA polymerase holoenzyme} ightarrow 	ext{mRNA}$$

Question 14

Which of the following is a key difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

Eukaryotic genes contain introns that are spliced out, while prokaryotic genes are continuous.

Question 15

Which of the following is NOT a role of general transcription factors (GTFs) in eukaryotic transcription?

Accepted Answer

Splicing introns from pre-mRNA

Question 16

Which of the following statements about the three nuclear RNA polymerases in eukaryotes is correct?

Accepted Answer

RNA polymerase II transcribes all protein-coding genes.

Question 17

Which of the following best describes the role of sequence-specific transcription factors in eukaryotic gene expression?

Accepted Answer

They bind to regulatory DNA elements and modulate the rate of transcription initiation.

Question 18

Which of the following equations represents the removal of introns from pre-mRNA in eukaryotes?

Accepted Answer

$$	ext{pre-mRNA} + 	ext{spliceosome} ightarrow 	ext{mature mRNA}$$

Question 19

Which of the following is a consequence of the coupling of transcription and translation in prokaryotes?

Accepted Answer

Protein synthesis can begin before transcription is complete.

Gene Expression: Transcription in Prokaryotes and Eukaryotes

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