Translation

Question 1

aminoacyl tRNA synthetase

Answer 1

Covalently link each amino acid to its correct tRNA (2 step mechanism).

Question 2

What direction is a protein synthesized?

Answer 2

From N terminus to C terminus (adds to C terminus).

Question 3

Small subunit

Answer 3

Provides frame work on which the tRNA are accurately matched to the codons of the mRNA.

Question 4

Large subunit

Answer 4

Catalyzes the formation of the peptide bonds.

Question 5

Where do the 2 subunits join together?

Answer 5

Near the 5’ end of mRNA.

Question 6

Peptidyl transferase

Answer 6

Enzyme in the large subunit that catalyzes the peptide bond formation between the amino acid chain on the tRNA in the P site and the amino acid on the tRNA in the A site.

Question 7

Bacterial ribosome

Answer 7

70S

Question 8

Eukaryotic ribosome

Answer 8

80S

Question 9

EF-Tu

Answer 9

Hydrolyzes GTP while trying to “swing” aminoacyl tRNA into the A site of the ribosome, it lets go when GTP is hydrolyzed.

Question 10

What are the 2 elongation factors in bacteria?

Answer 10

EF-Tu and EF-G.

Question 11

What are the 2 elongation factors in eukaryotes?

Answer 11

EF1 and EF2.

Question 12

EF-G

Answer 12

Brings a GTP that hydrolyzes and provides the energy for the small subunit to move.

Question 13

elF2

Answer 13

Bound to initiator tRNA when it binds to the small subunit.

Question 14

What happens after met-tRNA binds to the small subunit?

Answer 14

mRNA with elF4E and elF4G bind at the 5’ end recognized by the cap.

Question 15

What direction does the small subunit move?

Answer 15

5’ to 3’

Question 16

What are the three stop codons?

Answer 16

UAA, UAG and UGA.

Question 17

What does a release factor do?

Answer 17

Forces peptidyl transferase to catalyze an addiation of water instead of an amino acid.

Question 18

What do upf proteins do?

Answer 18

Triggers mRNA degradation if there are still EJC’s on mRNA when a stop codon is recognized.

Question 19

hsp70 and hsp60

Answer 19

Molecular chaperones that try to fix misfolded proteins by hydrolyzing ATP.

Question 20

Proteosome

Answer 20

Destroys proteins with a polyubiquintin chain.

Question 21

How is the ubiquitylation of a protein directed?

Answer 21

When the N terminal residue of a protein is acetylated, it is recognized by a specific E3 enzyme which directs it. If the protein is folded correctly, the acetlyated N terminus will be on the inside.