Question 1

Which of the following statements best describes the central dogma of molecular biology?

Accepted Answer

Information flows from DNA to RNA to protein.

Question 2

Which enzyme is responsible for catalyzing the synthesis of RNA from a DNA template during transcription?

Accepted Answer

RNA polymerase

Question 3

In prokaryotic cells, which feature allows translation of mRNA to begin before transcription is complete?

Accepted Answer

Lack of a nuclear envelope

Question 4

A researcher is studying a bacterial gene with a strong promoter. Which of the following elements is most likely to be present to enhance RNA polymerase binding?

Accepted Answer

UP element

Question 5

Which of the following best explains why errors in RNA transcription are generally less harmful than errors in DNA replication?

Accepted Answer

Many RNA copies are made from a single DNA template, so errors are less likely to persist.

Question 6

Which of the following is a function of the 5′ cap added to eukaryotic mRNA?

Accepted Answer

It protects mRNA from nucleases and helps position the mRNA on the ribosome.

Question 7

A mutation in the gene encoding the TATA-binding protein (TBP) would most directly affect which process?

Accepted Answer

Initiation of transcription by RNA polymerase II

Question 8

Which of the following best describes the role of the sigma (σ) factor in bacterial transcription?

Accepted Answer

It directs RNA polymerase to specific promoter sequences.

Question 9

A scientist isolates a eukaryotic mRNA and finds that it lacks a poly(A) tail. Which of the following is a likely consequence?

Accepted Answer

The mRNA will be rapidly degraded in the cytoplasm.

Question 10

Which of the following sequences marks the typical 5′ and 3′ splice sites of an intron in eukaryotic pre-mRNA?

Accepted Answer

GU at the 5′ end and AG at the 3′ end

Question 11

Which of the following best explains the evolutionary advantage of introns in eukaryotic genes?

Accepted Answer

They allow for alternative splicing and exon shuffling, increasing protein diversity.

Question 12

A patient is exposed to α-amanitin, a toxin from the death cap mushroom. Which RNA polymerase is most sensitive to this toxin, and what is the likely effect?

Accepted Answer

RNA polymerase II; inhibition of mRNA synthesis

Question 13

Which of the following best describes the process of alternative splicing?

Accepted Answer

A single pre-mRNA can be spliced in different ways to produce multiple protein products.

Question 14

During the termination of transcription in bacteria, which of the following is true for rho-independent termination?

Accepted Answer

A GC-rich hairpin loop forms in the RNA, followed by a series of U residues.

Question 15

Which of the following best explains why eukaryotic mRNA must be processed before translation?

Accepted Answer

Processing increases mRNA stability, facilitates export from the nucleus, and ensures correct translation.

Question 16

A mutation prevents the phosphorylation of the C-terminal domain (CTD) of RNA polymerase II. Which process would be most directly affected?

Accepted Answer

Coordinated RNA processing events such as capping, splicing, and polyadenylation

Question 17

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

Accepted Answer

Eukaryotes use multiple RNA polymerases and require general transcription factors.

Question 18

A scientist is studying RNA editing in trypanosome mitochondria. Which of the following best describes this process?

Accepted Answer

Insertion and deletion of uracil nucleotides guided by small RNAs

Question 19

Which of the following equations correctly represents the direction of RNA synthesis during transcription?

Accepted Answer

$$5' \rightarrow 3'$$

Question 20

A mutation in the branch point sequence of an intron would most likely disrupt which step of RNA processing?

Accepted Answer

Formation of the lariat structure during splicing

Gene Expression I: Transcription – Mechanisms, Regulation, and RNA Processing

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