Translation

Question 1

Accurate translation requires two steps…

Answer 1

1. correct match between tRNA and amino acid
2. correct match tRNA anticodon and mRNA codon

Question 2

aminoacyl-tRNA synthetase

Answer 2

Enzyme that joins each amino acid to the appropriate tRNA

Question 3

steps of aminoacyl-tRNA synthetase

Answer 3

1. Amino acid and tRNA enter active site
2. Using ATP, the synthetase catalyzes the covalent bonding of amino acid to its specific tRNA
3. tRNA, charged with its amino acid, is released by the synthetase

Question 4

Wobble

Answer 4

Flexible pairing at third base of codon; allow some tRNAs to bind to more than one codon

Question 5

P site

Answer 5

one of ribosome’s three binding site for tRNA in translation; P site holds tRNA carrying growing polypeptide chain

Question 6

A site

Answer 6

holds tRNA carrying next amino acid to be added to polypeptide chain

Question 7

E site

Answer 7

place where discharged tRNA leave the ribosome

Question 8

Three stages of translation

Answer 8

Initiation, elongation, termination

Question 9

Initiation

Answer 9

small ribsomal subunits bind to mRNA, large ribosomal subunit completes initiation complex; requires energy

Question 10

Elongation

Answer 10

Amino acids added one by one to C-terminus of growing chain
Three steps: codon recognition, peptide bond formation, translocation; energy

Question 11

Termination

Answer 11

1. Ribosome reaches stop codon on mRNA
2. Release factor promotes hydrolysis
3. Ribosomal subunits and other components dissociate

Question 12

Purpose of post-translational modification

Answer 12

alter biological activity or direct to specific locations in cell

Question 13

Polyribosomes

Answer 13

Group of several ribosome’s attached to, and translating the same mRNA molecules