Photocarcinogenesis Flashcards
1
Q
How can UV rays damage the skin?
A
UV light kills the cells by damaging their DNA
2
Q
Which base in DNA is affected by UV rays?
A
The UV light initiates a reaction between 2 thymine molecules
3
Q
UVA
A
Causes indirect DNA damage by inducing mutations
Rays penetrate deep into the dermis
Premature skin ageing and wrinkling
4
Q
UVA wavelength
A
320-400
5
Q
UVB
A
Causes direct DNA damage
Rays burn the superficial areas of the skin
Can cause skin cancer - more damaging than UVA
6
Q
UVB wavelength
A
290-320
7
Q
UVB induced DNA lesions (2 major types)
A
Cyclobutane pyrimidine dimers
Pyrimidine - pyrimidone
8
Q
UV signature mutation
A
TT -> AA
9
Q
Error prone DNA repair
A
Sometimes opposite the thymidine dimer (TT) the polymerase may accidentally insert the wrong base pairs i.e. GG instead of AA
