Question 1

Which of the following best describes the direction in which RNA polymerase synthesizes RNA during transcription?

Accepted Answer

RNA is synthesized in the 5' to 3' direction.

Question 2

During transcription in prokaryotes, what is the role of the sigma factor?

Accepted Answer

It binds to the promoter to help RNA polymerase recognize the start site.

Question 3

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

Accepted Answer

Eukaryotic transcription involves multiple transcription factors assembling at the promoter.

Question 4

What is the function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

It serves as a recognition signal for the ribosome during translation.

Question 5

A mutation prevents the formation of the hairpin loop in prokaryotic mRNA. What is the most likely consequence?

Accepted Answer

Transcription will not terminate properly, resulting in abnormally long mRNA.

Question 6

Which of the following best explains why transcription and translation are coupled in prokaryotes but not in eukaryotes?

Accepted Answer

Eukaryotic mRNA must be processed and exported from the nucleus before translation.

Question 7

Which enzyme is responsible for 'charging' tRNA molecules with their correct amino acids?

Accepted Answer

Aminoacyl-tRNA synthetase

Question 8

What would be the result if a tRNA is incorrectly charged with the wrong amino acid?

Accepted Answer

The wrong amino acid will be incorporated into the growing polypeptide.

Question 9

Which of the following statements about the 'wobble hypothesis' is correct?

Accepted Answer

It allows non-standard base pairing at the third position of the codon.

Question 10

A eukaryotic gene contains two exons and one intron. After transcription and mRNA processing, which regions will be present in the mature mRNA?

Accepted Answer

Only the exons

Question 11

Which of the following best describes the role of ribosomal RNA (rRNA) in translation?

Accepted Answer

It catalyzes peptide bond formation between amino acids.

Question 12

During translation, what is the function of the A site of the ribosome?

Accepted Answer

It holds the incoming aminoacyl-tRNA.

Question 13

Which of the following events occurs during the elongation phase of translation?

Accepted Answer

Peptide bonds are formed between amino acids.

Question 14

A mutation changes the sequence of a eukaryotic gene's poly(A) signal. What is the most likely effect?

Accepted Answer

Transcription termination will be impaired, possibly resulting in longer transcripts.

Question 15

Which of the following is a real-world example of the importance of accurate mRNA splicing?

Accepted Answer

Incorrect splicing can lead to diseases such as beta-thalassemia.

Question 16

Which of the following equations correctly represents the energy requirement for charging a tRNA with its amino acid?

Accepted Answer

$$\mathrm{Amino~acid} + \mathrm{tRNA} + \mathrm{ATP} \rightarrow \mathrm{Aminoacyl{-}tRNA} + \mathrm{AMP} + \mathrm{PP_i}$$

Question 17

Which of the following best explains why multiple ribosomes can translate a single mRNA molecule at the same time?

Accepted Answer

Ribosomes can bind to the mRNA before the previous ribosome has finished translation.

Question 18

Which of the following is NOT a product of transcription?

Accepted Answer

DNA polymerase

Question 19

A scientist isolates a eukaryotic mRNA and finds that it lacks a 5' cap and a poly(A) tail. What is the most likely consequence for this mRNA?

Accepted Answer

It will be rapidly degraded and not efficiently translated.

Mechanisms of Transcription and Translation

Study Guide - Practice Questions