Question 1

Which of the following statements best describes the genetic code used during translation?

Accepted Answer

The genetic code is degenerate, meaning that more than one codon can specify the same amino acid.

Question 2

A mutation changes the third base of a codon from C to U. Which property of the genetic code allows for the possibility that the amino acid sequence remains unchanged?

Accepted Answer

The code is degenerate.

Question 3

Which of the following best explains why there are fewer than 61 different tRNAs, even though there are 61 codons for amino acids?

Accepted Answer

Some tRNAs can recognize multiple codons due to the wobble hypothesis.

Question 4

Which of the following is the correct sequence of events during the charging of a tRNA by aminoacyl-tRNA synthetase?

Accepted Answer

ATP binds to synthetase, amino acid binds, AMP is attached to amino acid, tRNA replaces AMP, amino acid is attached to tRNA.

Question 5

What is the role of the Shine-Dalgarno sequence in prokaryotic translation?

Accepted Answer

It binds the ribosome to position the start codon at the P site.

Question 6

Which of the following best describes the function of molecular chaperones during protein synthesis?

Accepted Answer

They ensure proper folding of polypeptides and prevent incorrect interactions.

Question 7

During translation elongation, what type of bond is formed between amino acids, and what provides the energy for this reaction?

Accepted Answer

A peptide bond; energy from the cleavage of the ester bond between tRNA and amino acid.

Question 8

Which of the following is true regarding the initiation of translation in eukaryotes?

Accepted Answer

The small ribosomal subunit binds to the 5' cap of mRNA with the help of eIFs.

Question 9

A tRNA has the anticodon 5'-UCU-3'. Which mRNA codon will it recognize, and what amino acid will it carry?

Accepted Answer

5'-AGA-3'; Arginine

Question 10

Which of the following best explains why the hydrolysis of pyrophosphate (PP$$_i) $$during tRNA charging is considered highly exergonic?

Accepted Answer

It releases two phosphate groups, driving the reaction forward.

Question 11

Which of the following is NOT a function of aminoacyl-tRNA synthetase?

Accepted Answer

Catalyzing peptide bond formation between amino acids on the ribosome.

Question 12

Which of the following statements about the ribosome is correct?

Accepted Answer

The P site is where the first tRNA binds and peptide bond formation begins.

Question 13

A mutation eliminates the Shine-Dalgarno sequence in a prokaryotic mRNA. What is the most likely consequence?

Accepted Answer

The ribosome will not bind, and translation will not occur.

Question 14

Which of the following best describes the role of release factors during translation termination?

Accepted Answer

They bind to the stop codon and catalyze the release of the polypeptide chain.

Question 15

Which of the following equations correctly represents the reaction catalyzed by aminoacyl-tRNA synthetase?

Accepted Answer

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

Question 16

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

Accepted Answer

Eukaryotes use a 5' cap for ribosome binding, while prokaryotes use the Shine-Dalgarno sequence.

Question 17

A prokaryotic mRNA is described as polycistronic. What does this mean?

Accepted Answer

It encodes multiple proteins, each translated from a different coding region.

Question 18

Which of the following best explains the importance of the 'wobble' position in tRNA anticodons?

Accepted Answer

It allows a single tRNA to recognize multiple codons for the same amino acid.

Question 19

During translation, which site on the ribosome does the incoming aminoacyl-tRNA first bind?

Accepted Answer

A site

Translation: From mRNA to Protein – Mechanisms and Molecular Players

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