Question 1

Which of the following best describes the role of the promoter in transcription initiation?

Accepted Answer

It directs RNA polymerase to the correct DNA strand to begin transcription.

Question 2

During mRNA processing in eukaryotes, which modification is added to the 5' end of the transcript, and what is its primary function?

Accepted Answer

A methylguanosine cap; facilitates ribosome binding and export from the nucleus.

Question 3

Which equation correctly represents the central dogma of molecular biology?

Accepted Answer

$$DNA \rightarrow RNA \rightarrow Protein$$

Question 4

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

Accepted Answer

Translation will terminate prematurely due to a stop codon.

Question 5

Which feature distinguishes eukaryotic mRNA processing from prokaryotic mRNA processing?

Accepted Answer

Eukaryotic mRNA undergoes splicing, 5' capping, and poly-A tail addition.

Question 6

In the lactose operon of E. coli, what is the role of the repressor protein?

Accepted Answer

It binds to the operator to prevent transcription of the operon.

Question 7

Which of the following statements about ribosomes is correct?

Accepted Answer

Ribosomes are composed of small and large subunits and catalyze protein synthesis.

Question 8

A patient has a mutation in the spliceosome machinery. Which process will be most directly affected?

Accepted Answer

Removal of introns from pre-mRNA.

Question 9

Which of the following best explains why multiple codons can encode the same amino acid?

Accepted Answer

Redundancy in the genetic code.

Question 10

During translation, what is the function of tRNA?

Accepted Answer

tRNA brings amino acids to the ribosome and matches them to the codons in mRNA.

Question 11

Which process occurs in the nucleus of eukaryotic cells but not in prokaryotic cells?

Accepted Answer

Splicing of introns from pre-mRNA.

Question 12

A researcher observes that RNA polymerase incorporates approximately 60 nucleotides per second in eukaryotes. What cellular mechanism ensures the accuracy of this process?

Accepted Answer

Proofreading by RNA polymerase.

Question 13

Which of the following is a direct result of the polyadenylation signal during eukaryotic transcription termination?

Accepted Answer

Cleavage of the primary transcript and addition of a poly-A tail.

Question 14

Which of the following codons is a start codon and what amino acid does it encode?

Accepted Answer

AUG; methionine

Question 15

In eukaryotic cells, which sequence of events correctly describes the processing of pre-mRNA to mature mRNA?

Accepted Answer

5' capping, splicing, poly-A tail addition

Question 16

Which of the following statements about prokaryotic gene expression is correct?

Accepted Answer

mRNA does not require processing before translation.

Question 17

A scientist discovers a new eukaryotic gene with overlapping coding regions. What is the most likely explanation for this observation?

Accepted Answer

The gene can encode different proteins from the same DNA sequence.

Question 18

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

Accepted Answer

Signals the addition of a poly-A tail.

Question 19

Which of the following best describes the difference in promoter complexity between prokaryotes and eukaryotes?

Accepted Answer

Eukaryotic promoters are more complex, often requiring multiple regulatory elements.

Gene Expression: Transcription, Translation, and Regulation in Prokaryotes and Eukaryotes

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