M1 L3

Question 1

How many errors do classical pols make

Answer 1

errors ever 1/1000 nt

Question 2

what are classical DNA pols 4 options when it comes to a translesion site

Answer 2

1. Dissociate, external exonuclease comes in
2. 3’ proof reading ability
3. come off
4. If the wrong base has already been added it can be repaired through mismatch repair mechanism

Question 3

Example of disease caused by DNA damage

Answer 3

Xeroderma pigmentosum

Question 4

What Y family pol comes in first

Answer 4

REV1 then other DNA repair polymerases come in specific to what type of DNA damage there is

Question 5

why does DNA synthesis need to be accurate

Answer 5

small errors can have huge implications causing cancer and diseases.

lots of DNA is replicated all the time so there is lots of chance for errors to happen which could lead to a permanent mutation

Question 6

How many lesions happen in a human cell per day

Answer 6

5000

Question 7

What controls polymerase switching

Answer 7

PCNA. When pol comes across translesion then PCNA gets ubiquitinated causing replisome to dissociate

Question 8

Examples of TLS pols

Answer 8

eta, kappa and theta

Question 9

Xeroderma pigmentosum

Answer 9

Autosomal recessive human disease caused by mutation in TLS pol eta, prevents synthesis through pyrimidine dimers.

Causes extreme sensitivity to sunlight, development of cancer at site of UV exposure (bc mutations arent being fixed)