Lecture 14 Translation

Question 1

mRNA structure

Answer 1

5’ guanine tail
3’ AAAA tail
5’ UTR
3’ UTR
CDS

Question 2

Introns are…

Answer 2

spliced out

Question 3

Where can introns be spliced out

Answer 3

5’ UTR, 3’ UTR, CDS

Question 4

How does a specific mRNA sequence get
translated to a specific amino acid
sequence?

Answer 4

A given tRNA will only bind to one mRNA
codon
A given tRNA will only have type of amino acid
attached

Question 5

Anticodon

Answer 5

active site for base pairing on the tRNA with mRNA

Question 6

tRNA is transcribed from…

Answer 6

tRNA genes, tRNA is the final product

Question 7

AUG codon is…

Answer 7

the start

Question 8

Starting codon

Answer 8

AUG

Question 9

Ending Codons

Answer 9

UAA, UAG, UGA

Question 10

is the starting codon translated?

Answer 10

yes, the ending one is not

Question 11

Initiation steps (3)

Answer 11

1. small ribosomal subunit binds to mRNA
2. initiator tRNA binds at AUG codon
3. Large subunit then bonds

Question 12

Elongation step 1

Answer 12

Series of steps to add amino acids
The polypeptide is attached to tRNA in P site
new tRNA binds to mRNA at A site

Question 13

Elongation step 2

Answer 13

Polypeptide chain in P site transferred to tRNA in site A
Catalyzed by ribosome

Question 14

Elongation step 3

Answer 14

Translocation of ribosome along mRNA, (one codon shift down)
empty tRNA in E site
A site empty
tRNA with polypeptide chain in P site.

Question 15

Elongation step 4

Answer 15

Empty tRNA leaves ribosome in E site
polypeptide in P site with one more AA than at the start of cycle

Question 16

Termination

Answer 16

ribosome reaches codon, A site accepts the release factor
Release factor promotes hydrolysis, releasing polypeptide
subunits dissociate

Question 17

Difference in Prokaryotes

Answer 17

Prokaryotes can begin translation before transcription is over, eukaryotes cannot.