Translation

Question 1

Start codon

Answer 1

AUG

Question 2

Which end of tRNA contains the anticodon?

Answer 2

5’

Question 3

Which end of tRNA is attached to the amino acid?

Answer 3

3’

Question 4

Where does the energy come from that adds consecutive amino acids to the growing polypeptide chain?

Answer 4

Energy stored in the aa bond between 3’ end and tRNA

Question 5

Wobble base-pairing has what distinct evolutionary advantage?

Answer 5

Allows for fewer tRNAs

Question 6

Enzymes that assemble aa onto tRNAs

Answer 6

Aminoacyl-tRNA synthetases

Question 7

Which is correct:

A. Peptides are synthesized C–>N terminus
B. Peptides are synthesized N–>C terminus

Answer 7

B

Question 8

T/F Each amino acid carries with it the energetic bond used to attach it to the former aa

Answer 8

F it carries for the next aa

Question 9

Where are ribosomes produced?

Answer 9

Nucleolus (not just nucleus)

Question 10

This ribosomal subunit attaches to the mRNA first

Answer 10

Small subunit

Question 11

Function of small ribosomal subunit

Answer 11

Match tRNA to condon

Question 12

Function of large ribosomal subunit

Answer 12

Form peptide bonds

Question 13

Name and describe three pockets on ribosome complex attached to mRNA

Answer 13

A–aminoacyl (incoming)
P-peptide (existing)
E-exiting (tRNAs)

Question 14

T/F Only one tRNA can be attached in the ribosome complex at any one time

Answer 14

F, two

Question 15

Describe the steps in translation initiation in eukaryotes

Answer 15

1. Met tRNA is added to small subunit
2. Small subunit binds to 5’ end of mRNA, recognizes cap and initiation factors eIF4E and eIF4G
3. Small subunit alone moves along mRNA to find first AUG sequence
4. Initiation factors removed
5. Large subunit attached
6. Initiator tRNA occupies P site
7. Next tRNA can enter A site

Question 16

Describe eukaryotic translation elongation

Answer 16

1. Next tRNA binds in site A
2. Peptidyl transferase adds peptide to growing peptide
3. Conformation changes move ribosome 3 bp down and eject tRNA from E site

Question 17

These assist in elongation

Answer 17

Elongation factors EF-Tu and EF-G

Question 18

Describe translation termination

Answer 18

Protein release factors bind stop condons and add water to peptide chain, freeing final tRNA