Question 1

Which of the following best describes a polycistronic operon in prokaryotes?

Accepted Answer

An operon that encodes multiple proteins from a single mRNA transcript

Question 2

During transcription initiation in prokaryotes, what is the primary role of the sigma factor?

Accepted Answer

To bind to the promoter and recruit RNA polymerase

Question 3

Which of the following statements about the Shine-Dalgarno sequence is correct?

Accepted Answer

It helps align the ribosome with the start codon during prokaryotic translation initiation

Question 4

What is the function of the release factor during translation termination?

Accepted Answer

It recognizes the stop codon and promotes the release of the polypeptide from the ribosome

Question 5

Which of the following is NOT a role of the 5' cap in eukaryotic mRNA?

Accepted Answer

Initiating transcription by RNA polymerase II

Question 6

How many distinct RNA polymerases are found in eukaryotic cells, and what is the primary function of RNA polymerase II?

Accepted Answer

Three; RNA polymerase II synthesizes mRNA

Question 7

Which of the following best describes the difference between exons and introns in eukaryotic genes?

Accepted Answer

Exons are coding sequences retained in mature mRNA, while introns are non-coding sequences removed during RNA splicing

Question 8

A mutation in the Kozak sequence of a eukaryotic mRNA would most likely affect which process?

Accepted Answer

The efficiency of translation initiation

Question 9

Which of the following is true regarding the role of uracil in transcription?

Accepted Answer

Uracil replaces thymine in RNA, pairing with adenine during RNA synthesis

Question 10

In prokaryotic translation, what is the function of the anticodon loop of tRNA?

Accepted Answer

It base-pairs with the codon on mRNA to ensure correct amino acid incorporation

Question 11

Which of the following best explains why alternative splicing is important in eukaryotes?

Accepted Answer

It allows a single gene to produce multiple protein isoforms

Question 12

During prokaryotic transcription, what happens to RNA polymerase at the termination step?

Accepted Answer

It dissociates from the DNA template and releases the newly synthesized RNA

Question 13

Which of the following is a correct sequence of events in eukaryotic mRNA processing after transcription termination?

Accepted Answer

Addition of 5' cap, splicing of introns, addition of poly-A tail

Question 14

A bacterial cell is exposed to a mutation that disrupts the sigma factor. Which process will be most directly affected?

Accepted Answer

Transcription initiation

Question 15

Which of the following equations correctly represents the base pairing during transcription?

Accepted Answer

$$\mathrm{A}_{	ext{DNA}} ightarrow \mathrm{U}_{	ext{RNA}}$$

Question 16

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

Accepted Answer

Prokaryotes use the Shine-Dalgarno sequence, while eukaryotes use the Kozak sequence

Question 17

Which of the following best describes the role of the promoter region in transcription?

Accepted Answer

It is the DNA sequence where RNA polymerase binds to initiate transcription

Question 18

A patient has a genetic disorder affecting the polyadenylation signal in mRNA. Which process is most likely impaired?

Accepted Answer

Addition of the poly-A tail to mRNA, affecting mRNA stability and export

Question 19

Which of the following is the correct order of events during prokaryotic translation elongation?

Accepted Answer

Entry of charged tRNA, peptide bond formation, translocation of ribosome

Central Dogma: Transcription and Translation in Bacteria & Eukaryotes

Study Guide - Practice Questions