Question 1

Which of the following best describes the role of the Shine-Dalgarno sequence in prokaryotic translation initiation?

Accepted Answer

It aligns the ribosome with the start codon by base pairing with the 16S rRNA.

Question 2

During eukaryotic translation initiation, which sequence of events is correct?

Accepted Answer

The small ribosomal subunit binds the 5’ cap, scans for AUG, then the large subunit joins after eIFs are released.

Question 3

Which of the following statements about tRNA is FALSE?

Accepted Answer

The amino acid attachment site is at the 5’ end of the tRNA.

Question 4

Which of the following best explains the 'wobble' hypothesis in codon-anticodon pairing?

Accepted Answer

The third base of the codon can form non-standard base pairs with the first base of the anticodon.

Question 5

Which ribosomal RNA acts as the peptidyl transferase in eukaryotic ribosomes?

Accepted Answer

28S rRNA

Question 6

A mutation in the gene encoding eIF-2 that prevents its phosphorylation would most likely result in:

Accepted Answer

Increased global translation during cellular stress.

Question 7

Which of the following is a key difference between prokaryotic and eukaryotic mRNA translation initiation?

Accepted Answer

Eukaryotes scan from the 5’ cap to the first AUG, while prokaryotes align the ribosome via the Shine-Dalgarno sequence.

Question 8

Which of the following equations correctly represents the energy requirement for aminoacyl-tRNA formation?

Accepted Answer

$$\mathrm{AA} + \mathrm{tRNA} + \mathrm{ATP} \rightarrow \mathrm{AA{-}tRNA} + \mathrm{AMP} + \mathrm{PP_i}$$

Question 9

A patient has a mutation that prevents the release factor from binding to the ribosome. What is the most likely consequence?

Accepted Answer

The ribosome will stall at the stop codon, and the polypeptide will not be released.

Question 10

Which of the following best describes the function of eIF-2 in eukaryotic translation?

Accepted Answer

It brings the charged initiator tRNA to the small ribosomal subunit in a GTP-dependent manner.

Question 11

Which of the following scenarios would most likely result in increased translation of ferritin mRNA?

Accepted Answer

High levels of iron, causing dissociation of the iron regulatory protein from the IRE.

Question 12

Which of the following is TRUE regarding the directionality of translation?

Accepted Answer

mRNA is read 5’ to 3’ and protein is synthesized N to C.

Question 13

Which of the following best explains why eukaryotic mRNAs are typically monocistronic?

Accepted Answer

The ribosome scans from the 5’ cap and usually initiates at the first AUG, producing one protein per mRNA.

Question 14

A scientist introduces a mutation in the Kozak sequence surrounding the AUG start codon of a eukaryotic mRNA. What is the most likely effect?

Accepted Answer

Decreased efficiency of translation initiation at the mutated AUG.

Question 15

Which of the following is a direct result of GTP hydrolysis during translation initiation in eukaryotes?

Accepted Answer

Release of eIF-2 from the initiator tRNA after AUG recognition.

Question 16

Which of the following best describes the role of aminoacyl-tRNA synthetases?

Accepted Answer

They attach specific amino acids to their corresponding tRNAs using ATP.

Question 17

Which of the following mechanisms is used by microRNAs (miRNAs) to regulate translation?

Accepted Answer

They cause degradation of target mRNAs or inhibit their translation.

Question 18

Which of the following steps in translation requires the most energy input?

Accepted Answer

Elongation, due to repeated GTP hydrolysis for each amino acid addition and translocation.

Protein Synthesis and Processing: Translation and Regulation

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