Question 1

Which of the following best describes the role of the Shine–Dalgarno sequence in bacterial translation initiation?

Accepted Answer

It is a purine-rich sequence that base pairs with the 16S rRNA to position the ribosome at the start codon.

Question 2

A mutation changes the third base of a codon from U to C, but the amino acid sequence of the protein remains unchanged. Which concept explains this phenomenon?

Accepted Answer

Third-base wobble

Question 3

Which of the following is TRUE regarding the structure of a typical amino acid?

Accepted Answer

Each amino acid contains a central carbon, an amino group, a carboxyl group, and a unique R group.

Question 4

Which of the following statements about ribosomes is correct?

Accepted Answer

The bacterial ribosome is composed of a 30S small subunit and a 50S large subunit, forming a 70S ribosome.

Question 5

During translation elongation in bacteria, what is the role of EF-Tu?

Accepted Answer

It recruits charged tRNAs to the A site using GTP hydrolysis.

Question 6

A patient has a mutation in a gene encoding a tRNA synthetase. Which process is most directly affected?

Accepted Answer

The attachment of the correct amino acid to its tRNA

Question 7

Which of the following best explains why methionine is not always found at the N-terminus of mature eukaryotic proteins?

Accepted Answer

Methionine is often removed during posttranslational processing.

Question 8

Which of the following is a key difference between translation initiation in bacteria and eukaryotes?

Accepted Answer

Bacteria use a Shine–Dalgarno sequence to position the ribosome, while eukaryotes use a Kozak sequence.

Question 9

A researcher observes that a single mRNA molecule in a bacterial cell is being translated by multiple ribosomes simultaneously. What is this structure called?

Accepted Answer

Polyribosome (polysome)

Question 10

Which of the following codons is a stop codon in the genetic code?

Accepted Answer

$$\mathrm{UGA}$$

Question 11

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

Accepted Answer

They bind to stop codons in the A site and trigger the release of the polypeptide.

Question 12

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

Accepted Answer

The genetic code is universal with very few exceptions, mainly in mitochondria.

Question 13

A mutation in the intercistronic spacer of a bacterial polycistronic mRNA results in a longer spacer sequence. What is the most likely effect?

Accepted Answer

Ribosomes may dissociate before reaching the next start codon, reducing translation of downstream genes.

Question 14

Which of the following modifications is most likely to activate or inactivate a protein after translation?

Accepted Answer

Phosphorylation of specific amino acids

Question 15

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids in a polypeptide chain

Question 16

A tRNA with the anticodon $$5'	ext{CGA}3'$$ can recognize which mRNA codon, considering third-base wobble?

Accepted Answer

$$5'	ext{UCG}3'$$

Question 17

Which of the following is a real-life example of posttranslational processing?

Accepted Answer

Cleavage of proinsulin to produce functional insulin

Question 18

Which of the following best explains why bacteria can produce human insulin using recombinant DNA technology?

Accepted Answer

The genetic code is nearly universal, allowing bacterial ribosomes to translate human genes.

Question 19

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

Accepted Answer

Synthesizing tRNA molecules

Chapter 9: The Molecular Biology of Translation – Genetics Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard