DNA damage and repair

Question 1

What are the two types of mutations

Answer 1

Point mutations: substitution of one base pair for another

2. Insertions/deletions of one or more base (“indels”) - often generated by “DNA intercalating” agents

Question 2

What is a transition mutation

Answer 2

replacement of one purine by another purine

Question 3

What is a transversion mutation

Answer 3

Less frequently a purine is replaced by a pyrimidine or vice versa

Question 4

Describe deamination

Answer 4

Treatment of DNA with nitrous acid results in deamination of adenine, conversion to hypoxanthine

-Induces a mutation form A-T to G-C

Question 5

Describe alkylating agents

Answer 5

alkylating agents add a methyl (or an ethyl) group, usually to purines which disrupts H bonding

Question 6

Describe intercalation agents

Answer 6

Flat aromatic molecules such as can intercalate between adjacent base pairs in the DNA double helix. Their presence can lead to the insertion or deletion of one or more base pairs