IBS I Exam 2: Translation

What is the start codon?

AUG

What are the 3 stop codons

UAG, UAA, UGA

What is it called when different organisms have different preferences for certain codons

codon preference

What type of mutation occurs when you insert or delete nucleotides that aren’t in multiples of 3?

Frameshift mutation

What type of mutation occurs when you substitute a nucleotide and the amino acid gets changed, causing a change in the primary structure of a protein?

Missense mutation

What type of mutation occurs when a nucleotide is substituted, changing an amino acid codon into a stop codon?

Nonsense mutation

What is the enzyme that catalyzes the charging of tRNA with amino acid?

Amino-Acyl tRNA synthetase

What is the mechanism of action of mupirocin (Bactroban)

Prevents the charging of isoleucyl-tRNA by binding to isoleucyl-tRNA synthetase

What are the 3 tRNA binding sites on the ribosome?

A site, p site, E site

Role of A site in translation

Accepts new amino-acyl tRNA

P site role in translation

Where peptide bond formation occurs

E site function in translation

Ejection of the tRNA after the peptide is transferred

Tetracycline mechanism of action

Blocks amino-acyl tRNA from entering A site to stop translation

What is the chemical nature of peptidyltransferase?

rRNA

What are the two functions of peptidyl transferase?

Transfers peptide from tRNA in P site to charged tRNA in A site, releases full peptide at termination

What is it called when the mRNA with amino acids attached in the ribosome gets shifted forward 1 codon

Translocation

What is the mechanism of action of macrolides?

Binds reversibly to the 50s subunit of bacterial ribosome and interferes with translocation.

What are the 2 mechanisms of action of aminoglycosides

binds irreversibly to 30s ribosomal subunit and inhibits translation initiation, causes mRNA misreading during elongation

What is the energy requirement for protein translation?

4 high energy bonds