Question 1

Which of the following statements best describes the relationship between DNA, RNA, and protein in gene expression?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

A peptide bond forms between which two groups of adjacent amino acids during translation?

Accepted Answer

The amino group of one amino acid and the carboxyl group of the next amino acid.

Question 3

If a DNA sequence has 4 different bases and codes for 20 amino acids, what is the minimum number of bases per codon required to encode all amino acids?

Accepted Answer

3 bases per codon

Question 4

Which experiment provided genetic evidence that the genetic code is a triplet code?

Accepted Answer

Crick and Brenner’s proflavin-induced mutations in bacteriophage T4

Question 5

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

Accepted Answer

It binds the ribosome to the mRNA by base pairing with the 16S rRNA.

Question 6

Which property of the genetic code allows multiple codons to encode the same amino acid?

Accepted Answer

Degeneracy (redundancy)

Question 7

During translation elongation, what provides the energy for ribosome translocation?

Accepted Answer

GTP hydrolysis

Question 8

Which molecule is responsible for the peptidyl transferase activity in the ribosome?

Accepted Answer

Ribosomal RNA (rRNA)

Question 9

A mutation changes the DNA sequence from GAA to GAG. What effect will this have on the protein, given the genetic code is degenerate?

Accepted Answer

It may not change the amino acid due to degeneracy.

Question 10

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

Accepted Answer

The third base of the codon can pair with multiple bases in the tRNA anticodon.

Question 11

Which of the following is NOT a function of tRNA?

Accepted Answer

Catalyzing peptide bond formation

Question 12

In eukaryotic translation initiation, how does the ribosome locate the start codon?

Accepted Answer

By binding the 5’ cap and scanning downstream to the first AUG

Question 13

Which codon is universally used as the start codon in translation?

Accepted Answer

AUG

Question 14

What is the result when three proflavin-induced (+) mutations are combined in the T4 phage rII locus?

Accepted Answer

The wild-type function is restored.

Question 15

Which of the following best explains why the genetic code is considered nearly universal?

Accepted Answer

Most organisms use the same codons for most amino acids, with rare exceptions.

Question 16

Which stage of translation involves the ribosome encountering a stop codon and releasing the polypeptide?

Accepted Answer

Translation termination

Question 17

A mutation in the coding strand of DNA changes a codon from ATG to ATA. What is the effect on the protein sequence?

Accepted Answer

Methionine is replaced by isoleucine.

Question 18

Which of the following is true about the directionality of translation?

Accepted Answer

Proteins are synthesized from the amino terminus to the carboxyl terminus.

Question 19

Which of the following amino acids is encoded by only one codon?

Accepted Answer

Methionine

Question 20

What is the role of release factors (RFs) in translation?

Accepted Answer

They recognize stop codons and trigger release of the polypeptide.

Translation and the Genetic Code: From DNA to Protein

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