Question 1

Which of the following best describes the function of aminoacyl-tRNA synthetases during translation?

Accepted Answer

They attach the correct amino acid to its corresponding tRNA using ATP.

Question 2

A mutation changes the codon GAG to GTG in the β-globin gene. What is the consequence of this mutation at the protein level, and what disease does it cause?

Accepted Answer

It changes glutamic acid to valine, causing sickle cell disease.

Question 3

Which sequence is recognized by the ribosome in prokaryotes to initiate translation, and what is its function?

Accepted Answer

Shine–Dalgarno sequence; aligns the ribosome with the start codon

Question 4

Which of the following post-translational modifications is primarily responsible for targeting proteins for degradation by the proteasome?

Accepted Answer

Ubiquitination

Question 5

A eukaryotic mRNA is missing its 5’ cap. What is the most likely consequence for translation?

Accepted Answer

The ribosome will not recognize the mRNA, and translation initiation will fail.

Question 6

Which of the following best explains why the genetic code is described as 'degenerate'?

Accepted Answer

A single amino acid can be encoded by multiple codons.

Question 7

During translation elongation in bacteria, what is the role of EF-Tu?

Accepted Answer

It facilitates the entry of aminoacyl-tRNA into the A site.

Question 8

Which of the following is a direct result of a frameshift mutation caused by a single nucleotide insertion in an open reading frame (ORF)?

Accepted Answer

The reading frame is altered, potentially changing all downstream amino acids.

Question 9

Which of the following statements about tRNA is FALSE?

Accepted Answer

tRNAs do not require the addition of a CCA tail at the 3’ end.

Question 10

Which of the following best describes the function of the Kozak sequence in eukaryotic translation?

Accepted Answer

It enhances recognition of the start codon by the ribosome.

Question 11

A protein is found to be inactive until a specific peptide is removed from its N-terminus. Which post-translational modification is most likely responsible for its activation?

Accepted Answer

Proteolytic cleavage

Question 12

Which of the following is a key difference between bacterial and eukaryotic ribosomes?

Accepted Answer

Bacterial ribosomes are 70S, eukaryotic ribosomes are 80S.

Question 13

Which of the following best explains the importance of protein domains?

Accepted Answer

They fold into stable structures that impart specific functional capabilities to proteins.

Question 14

Which of the following is TRUE regarding the role of the signal recognition particle (SRP) during protein synthesis?

Accepted Answer

It recognizes signal sequences and directs ribosomes to the ER membrane.

Question 15

Which of the following post-translational modifications is most likely to regulate protein localization within the cell?

Accepted Answer

Lipidation

Question 16

A scientist observes that a protein is rapidly degraded after being tagged with a small protein called ubiquitin. Which lysine linkage is most commonly associated with this process?

Accepted Answer

K48-linked polyubiquitination

Question 17

Which of the following best describes the process by which a peptide bond is formed during translation?

Accepted Answer

A dehydration (condensation) reaction between the carboxyl group of one amino acid and the amino group of another

Question 18

Which of the following is a direct effect of phosphorylation as a post-translational modification?

Accepted Answer

It regulates enzyme activity and cell signaling.

Question 19

Which of the following is a real-life example of how a single nucleotide change can affect protein structure and function?

Accepted Answer

A mutation in the β-globin gene causing sickle cell anemia

Question 20

Which of the following best explains why tRNAs undergo extensive post-transcriptional modifications?

Accepted Answer

To increase translation accuracy and allow flexibility in codon recognition

Translation and Post-Translational Modifications in Genetics

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