MCB Chapter 8 (Memorization) (Translation)

Codons -

triplets of nucleotides with message encoded in the mRNA

Ribosomes -

machines that read the language of mRNA

How many codons are possible?

64 in total, 61 (amino acids), 3 (stop codons)

What are the stop codons?

(UAA, UGA, UAG)

What is the start codon?

AUG

tRNA -

Adaptor RNA attached to amino acids

Primary sequence of tRNA?

D, M, Y, T, and phi?

Class I aminoacyl tRNA synthetase

aminoacylates at the 2’-OH of a terminal adenosine on tRNA

Class II aminoacyl tRNA synthetase

aminoacylates at the 3’-OH of a terminal adenosine on tRNA

2 subunits of ribosome?

30S, 50S

What does the two subunits form?

70S (Ribosome)

Small subunit -

30S, contains 21 ribosomal proteins assembled around on 16s rRNA

Large subunit -

50S, contains 33 proteins around two rRNA (5S and 23S)

Shine-Dalgarno sequence

ribosome binding site, purine rich sequence

Peptidyltransferase

a ribozyme, carries out catalytic activity

How many binding sites does 70S ribosome have

3, for tRNA

P-site -

binds the tRNA with growing polypeptide chain

A- site -

binds incoming aminoacyl tRNA

E-site -

binds a tRNA recently stripped of polypeptide

Initiation -

brings two ribosomal subunits together and places first amino acid in position

Elongation -

sequentially adds amino acids

Termination -

releases completed protein and recycles ribosomal subunits

N-Formylmethionine -

used for initiation instead of methionine in bacteria

Polysomes -

multiple ribosomes performing translation on the same mRNA

Acetylation -

attachment of acetyl groups

Lipidation -

covalent attachment of lipids to proteins

Glycosylation -

attachment of sugars

Adenylation -

attachment of adenosine 5’ - monophosphate