Genetic Mutations and Translation Mechanisms in Molecular Biology

What is a stop codon mutation?

A mutation that causes the ribosome to fail to terminate translation, resulting in abnormally long non-functional proteins.

What happens during a star codon mutation?

The ribosome fails to initiate translation, leading to no protein being produced.

What is the role of the Shine-Dalgarno sequence?

It is a ribosomal binding site in bacterial mRNA that helps initiate translation.

What is a silent mutation?

A mutation that changes a codon but does not alter the amino acid produced due to the degeneracy of the genetic code.

What is a missense mutation?

A mutation that results in a change in one amino acid in the protein sequence, potentially altering its function.

What is a nonsense mutation?

A mutation that converts a regular codon into a stop codon, leading to premature termination of translation.

What is an example of a frameshift mutation?

An insertion or deletion of nucleotides that shifts the reading frame, altering all downstream codons.

What are the three steps of peptide synthesis from mRNA?

Initiation, elongation, and termination.

What initiates translation in eukaryotes?

The ribosome begins translation at the start codon (AUG) downstream of the 5' cap.

What is the function of tRNA during translation?

tRNA carries amino acids and has an anticodon that pairs with the corresponding codon on the mRNA.

What is the universal start codon?

AUG, which codes for methionine.

What are the stop codons in the genetic code?

UAA, UAG, and UGA, which do not encode any amino acids.

What is the genetic code's characteristic of being non-overlapping?

Codons do not share nucleotides; each codon is read independently.

What does it mean for the genetic code to be degenerate?

Most amino acids are encoded by more than one codon.

What is the significance of the codon-anticodon relationship?

It ensures that the correct amino acid is added to the growing polypeptide chain during translation.

What is the role of ribosomes in translation?

Ribosomes facilitate the binding of tRNA to mRNA and catalyze the formation of peptide bonds between amino acids.

What is the outcome of a frameshift mutation?

It typically results in a completely non-functional protein due to the alteration of the reading frame.

What is the function of the initiator tRNA?

It carries methionine and binds to the start codon (AUG) during initiation of translation.

What is the consequence of a missense mutation?

It can lead to reduced or altered protein function due to the change in amino acid sequence.

What happens during the elongation phase of translation?

Aminoacyl-tRNA enters the A site, and peptide bonds form between amino acids, extending the polypeptide chain.