Question 1

Which of the following statements best describes the directionality of RNA synthesis by RNA polymerase during transcription?

Accepted Answer

RNA polymerase synthesizes RNA in the 5' to 3' direction, using the template strand in the 3' to 5' direction.

Question 2

During transcription in prokaryotes, what is the role of the sigma ($$\sigma) $$factor?

Accepted Answer

It binds to the promoter region and helps RNA polymerase recognize the correct initiation site.

Question 3

Which of the following best explains why eukaryotic mRNA undergoes modifications such as 5' capping, splicing, and polyadenylation?

Accepted Answer

These modifications are necessary for mRNA to be exported from the nucleus and translated efficiently.

Question 4

A mutation causes the loss of the 3' splice site in a eukaryotic pre-mRNA. What is the most likely consequence?

Accepted Answer

The intron will be retained in the mature mRNA, potentially disrupting protein function.

Question 5

Which of the following equations correctly represents the formation of a peptide bond during translation?

Accepted Answer

$$\mathrm{Amino\ acid}_1 + \mathrm{Amino\ acid}_2 \rightarrow \mathrm{Dipeptide} + \mathrm{H}_2\mathrm{O}$$

Question 6

Which of the following is TRUE regarding the function of tRNA during translation?

Accepted Answer

tRNA brings specific amino acids to the ribosome by matching its anticodon to the mRNA codon.

Question 7

In eukaryotic cells, which event occurs FIRST during the processing of pre-mRNA?

Accepted Answer

Addition of the 5' cap.

Question 8

A researcher discovers a mutation in the gene encoding the translocase enzyme involved in translation. Which process would be most directly affected?

Accepted Answer

The movement of the ribosome along the mRNA during elongation.

Question 9

Which of the following best describes the role of the ribosome's A site during translation?

Accepted Answer

It is the site where incoming aminoacyl-tRNA binds to the mRNA codon.

Question 10

Which of the following statements about the genetic code is correct?

Accepted Answer

The genetic code is universal and degenerate, meaning multiple codons can code for the same amino acid.

Question 11

During translation, what is the consequence if a tRNA molecule is incorrectly charged with the wrong amino acid?

Accepted Answer

The wrong amino acid will be incorporated into the polypeptide, potentially altering protein function.

Question 12

Which of the following best describes the process of splicing in eukaryotic cells?

Accepted Answer

Removal of introns from pre-mRNA and joining of exons to form mature mRNA.

Question 13

Which of the following is a function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

It protects mRNA from degradation and assists in ribosome binding.

Question 14

A patient has a genetic disorder that prevents the addition of a poly-A tail to mRNA. What is the most likely effect on gene expression?

Accepted Answer

mRNA will be rapidly degraded, leading to reduced protein synthesis.

Question 15

Which of the following best describes the process of translocation during translation?

Accepted Answer

The ribosome moves one codon along the mRNA, shifting tRNAs from the A site to the P site and from the P site to the E site.

Question 16

Which of the following is a post-translational modification that can affect protein function?

Accepted Answer

Phosphorylation of specific amino acid residues.

Question 17

Which of the following equations represents the hydrolysis of GTP during translocation in translation?

Accepted Answer

$$\mathrm{GTP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{GDP} + \mathrm{P}_i$$

Question 18

Which of the following statements about prokaryotic mRNA is correct?

Accepted Answer

Prokaryotic mRNA is translated immediately after transcription without significant modification.

Question 19

Which of the following best explains the importance of the Shine-Dalgarno sequence in prokaryotic translation?

Accepted Answer

It helps the ribosome recognize the correct start site on the mRNA.

Transcription and Translation: Key Concepts in Gene Expression

Study Guide - Practice Questions