Protein synthesis

Transfer RNAs

tRNAs bind amino acids and take them to ribosomes to build

polypeptides

Aminoacyl tRNA Synthetase

covalently links amino acid to the

tRNA via a hydrogen bond between the OH and carboxyl group

Picture of tRNA

picture of amino acid

Aminoacylation

tRNA charging. Before translation can proceed, tRNA molecules must

be chemically linked to their respective amino acids

Aminoacyl tRNA synthetases

Enzymes that catalyze aminoacylation

• 20 different synthetases, one for each amino acid

• Highly specific; recognize only one amino acid

• Can recognize multiple tRNAs but only ones for

its amino acid

Wobble Hypothesis

Most tRNAs can bind multiple codons – the first two bases must be

specific bases but the anticodon can “wobble” on the third base.

Reading frame

Three ways in which the

sequence can be read in groups of three.

Each different way of reading encodes a

different amino acid sequence. TATA box dictates where to start the reading frame

Nonoverlapping

A single nucleotide may

not be included in more than one codon. Once three is has been read, it moves on to the next three

The universality of the code

near universal, with some exceptions

What are the 3 steps to translation

initiation, elongation, and termination

What are the characteristics of RNA code

Reading frame, nonoverlapping, and the universality of the code

What is the differnece between Eukaryote and prokaryote translation

Euk has tail and cap bind proteins and is scanned while in a circle to find the AUG or start codon

What are the prokaryotic translation factors

IF 2, EF-TU, EF-G, and RF 1

What are the eukaryotic translation factors

eIF 2, eEF1, eEF2, and eRF 1

What does IF2 or eIF2 do

delivers initiator tRNA to the P site of the ribosome

What does EF-Tu or eEF1do

delivers aminoacyl-tRNA to A site of ribosome during elongation

What does EF-G or eEF2 do

binds to A site to promote translocation following peptide bond formation

What does RF1 or eRF1 do

binds to A site at a stop codon and induces peptide transfer to water