Question 1

Which of the following statements correctly describes a key difference between transcription in prokaryotes and eukaryotes?

Accepted Answer

Eukaryotic transcription requires general and specific transcription factors, while prokaryotic transcription primarily relies on the sigma subunit.

Question 2

Given the template DNA strand 3'-TCAATAACTACA-5', what is the sequence of the transcribed mRNA?

Accepted Answer

5'-AGUUAUUGAUGU-3'

Question 3

Which component of prokaryotic RNA polymerase is responsible for recognizing and binding to promoter sequences?

Accepted Answer

Sigma subunit

Question 4

What is the function of the -10 and -35 consensus sequences in prokaryotic promoters?

Accepted Answer

They serve as binding sites for the sigma subunit of RNA polymerase to initiate transcription.

Question 5

Unlike DNA polymerase, RNA polymerase does not require which of the following to initiate synthesis?

Accepted Answer

A primer

Question 6

A primary RNA transcript contains two exons of 519 and 450 nucleotides and one intron of 330 nucleotides. What is the maximum number of amino acids in the encoded protein?

Accepted Answer

$$\frac{969 - 3}{3} = 322$$

Question 7

Which of the following best describes polycistronic mRNA?

Accepted Answer

An mRNA that encodes multiple proteins from a single transcript, commonly found in prokaryotes.

Question 8

What is the role of the polyadenylation signal sequence (AAUAAA) in eukaryotic transcription?

Accepted Answer

It signals where the transcript should be cleaved and the poly-A tail added.

Question 9

Which of the following is TRUE regarding the processing of eukaryotic mRNA?

Accepted Answer

Introns are removed and exons are ligated together during splicing.

Question 10

Which of the following statements about transcription termination in prokaryotes is correct?

Accepted Answer

Termination is signaled by a specific 40 bp sequence that causes RNA polymerase to dissociate.

Question 11

Which of the following is a consequence of missing the poly-A tail in eukaryotic mRNA?

Accepted Answer

The mRNA is rapidly degraded.

Question 12

Which of the following best explains why eukaryotic transcription requires chromatin remodeling?

Accepted Answer

Chromatin must be unpacked to allow transcription factors and RNA polymerase access to DNA.

Question 13

Which of the following is NOT a function of snRNPs (snurps) in eukaryotic cells?

Accepted Answer

Initiating transcription at the promoter.

Question 14

Which of the following sequences is most likely to be found at the 5' end of a mature eukaryotic mRNA?

Accepted Answer

A 7-methylguanosine cap

Question 15

Which of the following is a real-world example of a polycistronic mRNA in prokaryotes?

Accepted Answer

The lac operon mRNA encoding lacZ, lacY, and lacA proteins

Question 16

Which of the following best describes the role of enhancers in eukaryotic transcription?

Accepted Answer

Enhancers are cis-acting sequences that increase transcription when bound by activator proteins.

Question 17

A mutation removes the branch point sequence from an intron in a eukaryotic gene. What is the most likely consequence?

Accepted Answer

The intron will not be properly spliced out, leading to abnormal mRNA.

Question 18

Which of the following is TRUE about the direction of transcription?

Accepted Answer

RNA polymerase synthesizes RNA in the 5' to 3' direction.

Question 19

Which of the following is a key difference in mRNA processing between prokaryotes and eukaryotes?

Accepted Answer

Eukaryotic mRNA undergoes capping, polyadenylation, and splicing, while prokaryotic mRNA does not.

Transcription: Eukaryotes vs. Prokaryotes: Oct 24

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