Question 1

Which of the following best describes the difference between deoxyribose and ribose as shown in the structures above?

Accepted Answer

Deoxyribose has an H at the 2' carbon, while ribose has an OH at the same position.

Question 2

During transcription, which strand of DNA is used as the template for RNA synthesis, and what is the direction of RNA synthesis?

Accepted Answer

The template strand is used, and RNA is synthesized in the 5' to 3' direction.

Question 3

A DNA sequence on the non-template strand is 5’-AAGGCTT-3’. What will the RNA sequence be after transcription?

Accepted Answer

5’ – AAGGCUU – 3’

Question 4

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

Accepted Answer

Initiation of splicing of introns

Question 5

Which of the following statements about prokaryotic and eukaryotic transcription is correct?

Accepted Answer

Eukaryotic transcription requires general transcription factors, while prokaryotic transcription does not.

Question 6

Which RNA secondary structure is depicted in the fourth image above (with a single loop on one side)?

Accepted Answer

Stem-loop (hairpin)

Question 7

What is the role of the sigma (σ) factor in prokaryotic transcription?

Accepted Answer

It binds to the promoter and helps RNA polymerase recognize the start site.

Question 8

Which of the following is a key feature of Rho-independent termination in prokaryotes?

Accepted Answer

A hairpin structure forms in the RNA followed by a uracil-rich sequence.

Question 9

A mutation changes the GU at the 5’ splice site of an intron to AU. What is the most likely consequence?

Accepted Answer

The intron will not be recognized and will remain in the mature mRNA.

Question 10

Which of the following best explains why the -10 consensus sequence in prokaryotic promoters is AT-rich?

Accepted Answer

AT base pairs are easier to separate due to having only two hydrogen bonds.

Question 11

Which of the following is NOT a function of CRISPR/Cas9 in biotechnology?

Accepted Answer

Bringing back extinct species like the woolly mammoth

Question 12

A eukaryotic pre-mRNA has the following exon and intron structure: 5’UTR (50 bp) – Exon 1 (45 bp) – Intron 1 (100 bp) – Exon 2 (120 bp) – Intron 2 (35 bp) – Exon 3 (150 bp) – 3’UTR (50 bp). If the poly(A) tail is 100 bases, what is the length of the mature mRNA after proper splicing?

Accepted Answer

$$651$$

Question 13

Which of the following is a direct result of alternative splicing in eukaryotes?

Accepted Answer

A single gene can produce multiple protein isoforms.

Question 14

Which of the following is true regarding the directionality of transcription and the resulting RNA molecule?

Accepted Answer

RNA is synthesized in the 5’ to 3’ direction and is antiparallel to the template strand.

Question 15

Which of the following is a function of the 3’ poly(A) tail in eukaryotic mRNA?

Accepted Answer

It confers stability to the mRNA and aids in export from the nucleus.

Question 16

Which of the following best describes the role of general transcription factors (GTFs) in eukaryotic transcription?

Accepted Answer

They bind to the core promoter and recruit RNA polymerase II to initiate transcription.

Question 17

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

Accepted Answer

Eukaryotic transcription and translation are separated by the nuclear envelope.

Question 18

Which of the following is the correct sequence of events during prokaryotic transcription initiation?

Accepted Answer

Sigma factor binds to the promoter, RNA polymerase binds, DNA unwinds, RNA synthesis begins.

Question 19

A mutation in the polyadenylation signal sequence (AAUAAA) of a eukaryotic gene would most likely result in which of the following?

Accepted Answer

Failure to cleave the pre-mRNA and add a poly(A) tail.

Transcription and RNA Processing: Structure, Mechanism, and Regulation

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