Ultraviolet skin damage

Question 1

which causes direct DNA damage? UVA or UVB?

Answer 1

UVB

Question 2

which causes indirect oxidative damage

Answer 2

UVA

Question 3

which type of UV causes cyclobutane pyrimidine dimer s and 6-4 photoproducts

Answer 3

UVB

Question 4

describe the cyclobutane pyrimidine dimer

Answer 4

occurs when 2 OF THE SAME BASES ARE SIDE BY SIDE ON SAME STRAND

they are then COVALENTLY BONDED TO ONE ANOTHER

Question 5

which is more common? cyclobutane pyrimidine dimers or 6-4 photoproducts

Answer 5

cyclobutane pyrimidine is more common

6-4 photoproducts are more mutagenic

Question 6

describe the stability of both cyclobuatane pyrimidine dimers and 6-4 photoproducts

Answer 6

both are relatively stable and are removed by nucleotide excision repair

Question 7

what does UVA convert deoxyguanosine to by oxidising its bases

Answer 7

deoxyguanosine –> 8-oxo-deoxyguanosine

Question 8

what does a build up of 8-oxo-deoxyguanosine cause

Answer 8

causes GC –> AT point mutation

Question 9

what molecule repairs the oxidised bases

Answer 9

base excision repair

Question 10

what causes a depletion of langerhan cells in the skin and what does this result in

Answer 10

UV induced immunosuppression

lack of langerhan cells mean reduced ability to present antigens (langerhan cells are antigen presenting cells)

Question 11

in UV induced immunosuppression, T cells are involved. true?

Answer 11

yes - there is generation of UV induced regulatory T cells which have an immunosuppressive activity