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 prokaryotic transcription, which molecule recognizes the promoter and initiates transcription?

Accepted Answer

Sigma factor

Question 3

What is the role of the Shine-Dalgarno sequence in prokaryotic translation?

Accepted Answer

It aligns the ribosome with the start codon on mRNA

Question 4

Which of the following is TRUE regarding the difference between monocistronic and polycistronic mRNA?

Accepted Answer

Monocistronic mRNA encodes one protein, while polycistronic mRNA encodes multiple proteins

Question 5

Which base is incorporated into RNA instead of thymine during transcription?

Accepted Answer

Uracil

Question 6

In prokaryotic translation, what is the function of the release factor?

Accepted Answer

It recognizes the stop codon and promotes termination of translation

Question 7

Which of the following statements about eukaryotic RNA polymerases is correct?

Accepted Answer

Eukaryotes have three main RNA polymerases, each responsible for transcribing different types of RNA

Question 8

What is the primary function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

It protects mRNA from degradation and assists in ribosome binding during translation

Question 9

Which process allows a single eukaryotic gene to produce multiple different proteins?

Accepted Answer

Alternative splicing

Question 10

During prokaryotic transcription, what is the difference between upstream and downstream relative to the promoter?

Accepted Answer

Upstream refers to sequences before the promoter (toward 5' end), downstream refers to sequences after the promoter (toward 3' end)

Question 11

Which of the following is NOT a function of transcription factors in eukaryotic transcription?

Accepted Answer

Splicing introns from mRNA

Question 12

What happens to RNA polymerase after termination of transcription in prokaryotes?

Accepted Answer

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

Question 13

Which of the following correctly matches the start codon and its corresponding amino acid?

Accepted Answer

AUG — Methionine

Question 14

In eukaryotic mRNA processing, what is the role of the poly A tail?

Accepted Answer

It stabilizes mRNA and facilitates export from the nucleus

Question 15

Which of the following statements about exons and introns is correct?

Accepted Answer

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

Question 16

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

Accepted Answer

Initiation of translation

Question 17

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

Accepted Answer

$$\mathrm{A} \rightarrow \mathrm{U}$$, $$\mathrm{T} \rightarrow \mathrm{A}$$, $$\mathrm{C} \rightarrow \mathrm{G}$$, $$\mathrm{G} \rightarrow \mathrm{C}$$

Question 18

Which of the following best explains the role of regulatory proteins in operon function?

Accepted Answer

They bind to operator regions to increase or decrease transcription of structural genes

Question 19

A patient is found to have a mutation that prevents the addition of a 5' cap to mRNA. Which of the following consequences is most likely?

Accepted Answer

The mRNA will be rapidly degraded and translation efficiency will decrease

Question 20

Which of the following steps occurs after DNA transcription termination in eukaryotes?

Accepted Answer

RNA processing, including splicing and addition of 5' cap and poly A tail

Central Dogma: Transcription and Translation in Bacteria & Eukaryotes

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