Question 1

Which of the following best describes the role of the TATA box in eukaryotic transcription initiation?

Accepted Answer

It is a promoter element that helps position RNA polymerase II at the correct transcription start site.

Question 2

During transcription elongation, RNA polymerase II synthesizes RNA in which direction?

Accepted Answer

5' to 3' direction along the template strand

Question 3

Which modification is added to the 5' end of eukaryotic pre-mRNA to protect it from degradation and assist in translation initiation?

Accepted Answer

7-methylguanosine cap

Question 4

A mutation removes the polyadenylation signal sequence ($$AAUAAA) $$from a gene. What is the most likely consequence?

Accepted Answer

The mRNA will lack a poly-A tail, making it unstable and prone to degradation.

Question 5

Which of the following statements about alternative splicing is correct?

Accepted Answer

It enables the production of different protein isoforms from the same gene by varying exon inclusion.

Question 6

What is the function of the spliceosome during mRNA processing?

Accepted Answer

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

Question 7

Which codon serves as the universal start codon for translation in eukaryotes?

Accepted Answer

$$AUG$$

Question 8

A researcher mutates the 5' splice site of an intron from $$GU to$$ $$GC. $$What is the most likely effect on mRNA processing?

Accepted Answer

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

Question 9

Which of the following best explains why mRNA must be processed before translation in eukaryotes?

Accepted Answer

To stabilize the mRNA, facilitate export from the nucleus, and ensure accurate translation.

Question 10

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

Accepted Answer

Splicing of introns

Question 11

During translation, which molecule brings amino acids to the ribosome according to the codon sequence of mRNA?

Accepted Answer

tRNA

Question 12

A mutation changes the codon $$UAC ($$tyrosine) to $$UAA in an $$mRNA sequence. What is the most likely result?

Accepted Answer

Translation will terminate prematurely at the $$UAA$$ stop codon.

Question 13

Which of the following sequences is recognized as a polyadenylation signal in eukaryotic mRNA processing?

Accepted Answer

$$AAUAAA$$

Question 14

Which of the following statements about ribosomes is correct?

Accepted Answer

They consist of rRNA and proteins and are the site of polypeptide synthesis.

Question 15

If a gene contains three exons and two introns, how many exons will be present in the mature mRNA after splicing?

Accepted Answer

Three

Question 16

Which of the following is a direct consequence of the absence of a 5' cap on eukaryotic mRNA?

Accepted Answer

The mRNA will be rapidly degraded by exonucleases.

Question 17

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

Accepted Answer

Alternative splicing

Question 18

What is the role of the poly-A binding protein (PABP) in mRNA processing?

Accepted Answer

It stabilizes the poly-A tail and protects mRNA from degradation.

Question 19

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

Accepted Answer

The mRNA sequence is identical to the coding strand except that uracil ($$U) $$replaces thymine ($$T).$$

Question 20

A patient has a mutation that prevents the formation of the spliceosome. What is the most likely effect on gene expression?

Accepted Answer

Pre-mRNA will retain introns, resulting in abnormal or nonfunctional proteins.

Transcription and Translation: Mechanisms and Regulation in Eukaryotes

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