DNA Damage & Modifications

Question 1

Non-ionizing Radiation

Answer 1

caused by UV rays, covalent link between two pyrimidines (TT, CT) and makes pyrimidine dimers

repaired by: direct repair

Question 2

Ionizing Radiation

Answer 2

caused by Xrays, breaks double helix

Question 3

Spontaneous Damage

Answer 3

Depurination or Deaminiation

Question 4

Depurination

Answer 4

caused by: breaking the covalent n-glycosidic bond, removes a purine from DNA (left w just sugar and phosphate)

repaired by: Base excision

Question 5

Deamination

Answer 5

caused by removal of amino group, changes bases so cysteine becomes uracil, adenine becomes hypoxanine, and guanine becomes xanine

Question 6

Thymine modifications

Answer 6

replaced T w a G to silence the gene in CpG sites–> good for cancer

Question 7

intercalation

Answer 7

agents that come in between stacked bases which break and unwind base pairs