Question 1

Which of the following best describes the direction in which a polypeptide is synthesized during translation?

Accepted Answer

From the N (amino) terminus to the C (carboxyl) terminus

Question 2

A mutation changes the DNA sequence from $$5'\ ATG\ ACA\ CTG\ GGT\ ACG\ CTT\ TAA\ 3' to$$ $$5'\ ATG\ ACA\ CTG\ GGA\ ACG\ CTT\ TAA\ 3'. $$What is the effect on the encoded protein sequence?

Accepted Answer

A single amino acid is changed from Gly to Gly, so the sequence is unchanged.

Question 3

Which of the following statements about peptide bond formation is correct?

Accepted Answer

Peptide bond formation is a dehydration synthesis (condensation) reaction.

Question 4

During translation elongation, what is the correct order of tRNA movement through the ribosomal sites?

Accepted Answer

A site → P site → E site

Question 5

A tRNA with the anticodon $$5'\ UAC\ 3'$$ will pair with which mRNA codon?

Accepted Answer

$$5'\ AUG\ 3'$$

Question 6

Which enzyme is responsible for attaching the correct amino acid to its corresponding tRNA?

Accepted Answer

Aminoacyl tRNA synthetase

Question 7

In a eukaryotic cell, where does translation occur?

Accepted Answer

In the cytoplasm

Question 8

What is the function of the ribosome's P (peptidyl) site during translation?

Accepted Answer

It holds the tRNA to which the growing polypeptide chain is attached.

Question 9

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

Accepted Answer

Some amino acids are coded for by more than one codon.

Question 10

A researcher isolates a polysome from a cell. What does this indicate about the mRNA associated with the polysome?

Accepted Answer

The mRNA is being actively translated by multiple ribosomes.

Question 11

Which of the following events occurs during translation termination?

Accepted Answer

A release factor binds to the stop codon in the A site.

Question 12

Given the mRNA sequence $$5'\ AUG\ ACA\ CUG\ GGU\ ACG\ CUU\ UAA\ 3'$$, what is the corresponding amino acid sequence?

Accepted Answer

Met-Thr-Leu-Gly-Thr-Leu-Stop

Question 13

Which of the following is NOT a function of the ribosome during translation?

Accepted Answer

Attaching amino acids to tRNAs

Question 14

A mutation introduces a premature stop codon (nonsense mutation) in the middle of a gene. What is the most likely effect on the resulting protein?

Accepted Answer

The protein will be truncated and likely nonfunctional.

Question 15

Which of the following best describes the role of the 3' untranslated region (3' UTR) of an mRNA?

Accepted Answer

It is the region after the stop codon and is not translated.

Question 16

In prokaryotes, what is a key difference in the process of translation compared to eukaryotes?

Accepted Answer

Transcription and translation are coupled, occurring simultaneously.

Question 17

A patient has a genetic disorder caused by a mutation in an aminoacyl tRNA synthetase gene. Which process is most directly affected?

Accepted Answer

Attachment of amino acids to tRNAs

Question 18

Which of the following best explains why methionine is often the first amino acid in newly synthesized proteins?

Accepted Answer

The start codon AUG codes for methionine.

Question 19

If a tRNA is described as 'charged,' what does this mean?

Accepted Answer

It is attached to its specific amino acid.

Question 20

A scientist mutates the anticodon of a tRNA so that it now recognizes a stop codon. What is a likely consequence in translation?

Accepted Answer

An amino acid may be incorporated at the stop codon, resulting in a longer protein.

Translation and the Genetic Code: Structure, Function, and Mechanism

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