Question 1

Which of the following best describes the direction in which the ribosome reads the mRNA during translation?

Accepted Answer

5' to 3'

Question 2

A mutation in the coding region of a gene changes the DNA sequence from 5'-GAA-3' to 5'-GAG-3'. What is the effect on the encoded protein?

Accepted Answer

There is no change in the amino acid sequence (silent mutation).

Question 3

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

Accepted Answer

The code is overlapping, so each base is part of more than one codon.

Question 4

During translation, which molecule is responsible for bringing the correct amino acid to the ribosome by matching its anticodon to the mRNA codon?

Accepted Answer

tRNA

Question 5

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

Accepted Answer

It base-pairs with the 16S rRNA to position the ribosome at the start codon.

Question 6

Which of the following best explains why the genetic code must be read in triplets?

Accepted Answer

There are only 4 nucleotides and 20 amino acids, so single or double nucleotide codons are insufficient.

Question 7

A tRNA with the anticodon 5'-GAG-3' will pair with which mRNA codon?

Accepted Answer

5'-CUC-3'

Question 8

Which of the following is a property of peptide bonds in proteins?

Accepted Answer

They are covalent bonds between the carboxyl group of one amino acid and the amino group of the next.

Question 9

Which of the following best describes the function of aminoacyl-tRNA synthetase?

Accepted Answer

It attaches the correct amino acid to its corresponding tRNA.

Question 10

What is the consequence of a single base-pair insertion in the coding region of a gene?

Accepted Answer

It causes a frameshift mutation, altering the reading frame of the gene.

Question 11

Which of the following statements about translation termination is correct?

Accepted Answer

A stop codon is recognized by a protein release factor, not a tRNA.

Question 12

Which of the following best describes the 'wobble' position in codon-anticodon pairing?

Accepted Answer

It is the third base of the codon and allows for non-standard base pairing, enabling one tRNA to recognize multiple codons.

Question 13

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

Accepted Answer

Synthesizing tRNA molecules.

Question 14

In the Crick and Brenner experiment with T4 bacteriophage, what was the key evidence that the genetic code is a triplet code?

Accepted Answer

Combining three insertions or three deletions restored the wild-type phenotype.

Question 15

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

Accepted Answer

Most amino acids are encoded by more than one codon.

Question 16

Which of the following is the correct sequence of events in gene expression from DNA to protein?

Accepted Answer

Transcription → translation → protein folding

Question 17

A mutation changes the start codon (AUG) in an mRNA to AUA. What is the most likely consequence?

Accepted Answer

Translation will initiate at the next downstream AUG codon.

Question 18

Which of the following statements about aminoacyl-tRNA synthetases is correct?

Accepted Answer

There is one aminoacyl-tRNA synthetase for each amino acid.

Question 19

Which of the following best describes the chemical reaction that forms a peptide bond?

Accepted Answer

A condensation reaction between the carboxyl group of one amino acid and the amino group of another, releasing water.

Question 20

Which of the following is a property of the start codon in translation?

Accepted Answer

It codes for methionine (AUG) and sets the reading frame for translation.

Translation and the Genetic Code: From DNA to Protein

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