Question 1

Which of the following best describes the difference between the coding strand and the template strand during transcription?

Accepted Answer

The coding strand has the same sequence as the mRNA (except T is replaced by U), while the template strand is used by RNA polymerase to synthesize mRNA.

Question 2

Which of the following is a unique feature of RNA compared to DNA?

Accepted Answer

RNA contains ribose sugar and the base uracil (U) instead of thymine (T).

Question 3

A mutation in the -10 consensus sequence (Pribnow box) of a bacterial promoter would most likely result in:

Accepted Answer

Decreased binding of RNA polymerase, leading to reduced transcription initiation.

Question 4

Which of the following best explains why RNA polymerase does not have proofreading (exonuclease) activity like DNA polymerase?

Accepted Answer

Mistakes in RNA are less critical because RNA is not inherited and is usually short-lived.

Question 5

Which of the following RNA types is directly involved in removing introns from pre-mRNA in eukaryotes?

Accepted Answer

snRNA

Question 6

During rho-independent (intrinsic) termination in bacteria, which of the following features is essential for termination to occur?

Accepted Answer

A GC-rich inverted repeat followed by a string of uracils in the mRNA.

Question 7

Which of the following is NOT a function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

Initiation of polyadenylation at the 3' end.

Question 8

A eukaryotic gene is found to produce multiple different mRNA transcripts in different tissues. Which mechanism most likely explains this observation?

Accepted Answer

Alternative splicing of pre-mRNA.

Question 9

Which of the following best describes the role of the sigma (σ) subunit in bacterial RNA polymerase?

Accepted Answer

It is required for promoter recognition and initiation of transcription.

Question 10

Which of the following correctly matches the eukaryotic RNA polymerase with its primary function?

Accepted Answer

RNA Polymerase II: transcribes mRNA and most snRNA

Question 11

Which of the following is a consensus sequence commonly found in eukaryotic promoters and is important for transcription initiation?

Accepted Answer

TATA box (TATAAA)

Question 12

A mutation that disrupts the branch site adenine in a eukaryotic intron would most likely result in:

Accepted Answer

Failure to properly splice the intron, leading to retention of the intron in the mature mRNA.

Question 13

Which of the following best explains why eukaryotic mRNAs are generally more stable than bacterial mRNAs?

Accepted Answer

Eukaryotic mRNAs are protected by a 5' cap and a 3' poly-A tail.

Question 14

Which of the following statements about enhancers is TRUE?

Accepted Answer

Enhancers increase transcription by binding activator proteins, which can interact with the promoter even from a distance.

Question 15

Which of the following is the correct sequence of events during eukaryotic mRNA processing?

Accepted Answer

5' capping, splicing, 3' polyadenylation (order may overlap, but all occur before export)

Question 16

A researcher discovers a new RNA molecule that is double-stranded, regulates gene expression, and interacts with mRNA. Which type of RNA is this most likely to be?

Accepted Answer

siRNA

Question 17

Which of the following equations correctly represents the base-pairing rules for RNA during transcription?

Accepted Answer

$$A_{DNA} \rightarrow U_{RNA}$$, $$T_{DNA} \rightarrow A_{RNA}$$, $$G_{DNA} \rightarrow C_{RNA}$$, $$C_{DNA} \rightarrow G_{RNA}$$

Question 18

Which of the following is a real-world consequence of alternative splicing in humans?

Accepted Answer

It allows a single gene to produce multiple protein isoforms, contributing to tissue-specific functions.

Question 19

Which of the following best describes the function of the poly-A tail in eukaryotic mRNA?

Accepted Answer

It increases mRNA stability and facilitates export from the nucleus.

Transcription and RNA Processing: Structure, Mechanisms, and Regulation

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