Q: Which of the following sequences would be found at the 3’ end of a mature eukaryotic mRNA?

$$\text{AAAAAA...} ($$poly-A tail)

Question 1

Which of the following statements best describes the role of the sigma factor in prokaryotic transcription?

Accepted Answer

It is a transcription factor that enables RNA polymerase to recognize and bind to the promoter region in prokaryotes.

Question 2

During eukaryotic mRNA processing, which modification is essential for the stability and translation of the mRNA?

Accepted Answer

Addition of a 5’ methylguanosine cap and a 3’ poly-A tail

Question 3

Which of the following best explains why only one DNA strand is transcribed during transcription?

Accepted Answer

RNA polymerase can only bind to one strand at a time, producing an mRNA complementary to the template strand.

Question 4

A mutation in the TATA box of a eukaryotic gene would most likely result in which of the following?

Accepted Answer

Failure to properly initiate transcription

Question 5

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

Accepted Answer

Eukaryotic transcription requires a complex set of general transcription factors, while prokaryotic transcription primarily requires a sigma factor.

Question 6

Which of the following sequences would be found at the 3’ end of a mature eukaryotic mRNA?

Accepted Answer

$$	ext{AAAAAA...} ($$poly-A tail)

Question 7

A researcher isolates a eukaryotic mRNA and finds that it contains both exons and introns. What is the most likely explanation?

Accepted Answer

The mRNA has not yet undergone splicing.

Question 8

Which of the following best describes the function of the spliceosome?

Accepted Answer

It removes introns from pre-mRNA and joins exons together.

Question 9

In prokaryotes, what is the consequence of a mutation that prevents the formation of a hairpin loop in the mRNA during transcription termination?

Accepted Answer

Transcription will not terminate efficiently, leading to longer transcripts.

Question 10

Which of the following is true regarding the directionality of transcription?

Accepted Answer

RNA is synthesized in the 5’ to 3’ direction, using the 3’ to 5’ DNA template strand.

Question 11

Which of the following best explains why eukaryotic gene regulation is more complex than prokaryotic gene regulation?

Accepted Answer

Eukaryotic genes are often regulated by multiple transcription factors, enhancers, and chromatin structure.

Question 12

A mutation eliminates the branch site in a pre-mRNA intron. What is the most likely outcome?

Accepted Answer

The intron will not be removed, and the mature mRNA will contain extra sequences.

Question 13

Which of the following is a function of general transcription factors (GTFs) in eukaryotic transcription?

Accepted Answer

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

Question 14

Which of the following best describes the relationship between the coding strand of DNA and the mRNA produced during transcription?

Accepted Answer

The mRNA is identical to the coding strand except that uracil replaces thymine.

Question 15

Which of the following is a real-life application of understanding polycistronic mRNA in prokaryotes?

Accepted Answer

Designing bacterial expression vectors to produce multiple proteins from a single mRNA transcript.

Question 16

A scientist is studying a gene that is only expressed during early development and is later silenced. Which mechanism is most likely responsible for this gene silencing?

Accepted Answer

Transcription factors that close chromatin and repress transcription

Question 17

Which of the following best describes the function of the 5’ cap in eukaryotic mRNA?

Accepted Answer

It is required for the mRNA to bind to the ribosome for translation.

Question 18

Which of the following is a consequence of a mutation that prevents the dissociation of the sigma factor from RNA polymerase in prokaryotes?

Accepted Answer

RNA polymerase will not efficiently transition to elongation, reducing overall transcription.

Question 19

A patient has a genetic disorder caused by improper splicing of pre-mRNA. Which of the following is the most likely molecular explanation?

Accepted Answer

A mutation in the splice site prevents the spliceosome from recognizing the intron-exon boundary.

Transcription and mRNA Processing in Prokaryotes and Eukaryotes

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