Question 1

Which of the following statements best describes the directionality of mRNA translation by the ribosome?

Accepted Answer

The ribosome reads the mRNA from 5' to 3' and synthesizes the polypeptide from the N-terminus to the C-terminus.

Question 2

A mutation changes the DNA coding strand sequence from 5'-ATG GGG CCC TTT AAA TAG-3' to 5'-ATG GGA CCC TTT AAA TAG-3'. What is the effect on the resulting polypeptide?

Accepted Answer

A single amino acid will be changed from glycine to alanine.

Question 3

Which of the following best explains why there are fewer than 61 types of tRNA molecules in most cells?

Accepted Answer

Some tRNAs can recognize multiple codons due to third-base wobble.

Question 4

During bacterial translation initiation, which component is responsible for recognizing the Shine-Dalgarno sequence?

Accepted Answer

The 16S rRNA of the small ribosomal subunit

Question 5

Which of the following is NOT a stop codon in the standard genetic code?

Accepted Answer

AUG

Question 6

In eukaryotic translation initiation, what is the function of the Kozak sequence?

Accepted Answer

It is the consensus sequence that helps the ribosome identify the start codon.

Question 7

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

Accepted Answer

It attaches the correct amino acid to its corresponding tRNA using ATP.

Question 8

A patient has a mutation in the gene encoding the 18S rRNA. Which process is most likely to be directly affected?

Accepted Answer

Translation initiation in eukaryotes

Question 9

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

Accepted Answer

The code is redundant, meaning multiple codons can specify the same amino acid.

Question 10

During translation elongation, which site on the ribosome does the incoming charged tRNA first enter?

Accepted Answer

A site

Question 11

A single nucleotide insertion occurs in the coding region of a gene. What is the most likely consequence for the resulting protein?

Accepted Answer

A frameshift mutation will occur, altering the reading frame and likely producing a nonfunctional protein.

Question 12

Which of the following events occurs LAST during translation initiation in both prokaryotes and eukaryotes?

Accepted Answer

Joining of the large ribosomal subunit to form the complete ribosome

Question 13

Which of the following best explains why a single nucleotide change in the hemoglobin gene can cause sickle cell anemia?

Accepted Answer

It changes one amino acid, altering the protein's structure and function.

Question 14

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

Accepted Answer

Prokaryotes can couple transcription and translation, while eukaryotes separate these processes.

Question 15

Which of the following best describes the function of the E site on the ribosome?

Accepted Answer

It is where the uncharged tRNA exits the ribosome after its amino acid has been added to the polypeptide.

Question 16

A mutation in the Shine-Dalgarno sequence of a bacterial mRNA would most likely result in which of the following?

Accepted Answer

Failure of the ribosome to recognize the start codon, reducing translation efficiency.

Question 17

Which of the following best describes the role of GTP hydrolysis during translation?

Accepted Answer

It provides energy for ribosomal translocation and subunit joining.

Question 18

Which of the following is true regarding the universality of the genetic code?

Accepted Answer

The genetic code is nearly universal, with only a few exceptions in some organelles and microorganisms.

Question 19

Which of the following best explains the effect of a non-frameshift (in-frame) indel in a coding region?

Accepted Answer

It adds or removes one or more amino acids without altering the reading frame.

Chapter 9

Guida di studio - Domande di pratica

Study guide - Flashcard