DNA Damage

Question 1

Biological targets of toxicants

Answer 1

protein, polysaccahride, lipids, RNA/DNA

Question 2

Spontaneous alterations of and damage to DNA

Answer 2

replication errors cause mismatches - DNA repair reduces mutation rate

Question 3

Spontaneous alteration in DNA bases

Answer 3

loss of bases
deamination of bases
incorporation of uracil into DNA during semi-conservative replication
DNA damage generated oxygen radicals

Question 4

DNA damage generated by endogenous toxicants

Answer 4

1. spontaneous alteration of and damage to DNA

2. spontaneous alteration in DNA bases

Question 5

DNA damage generated by environmental toxicants

Answer 5

physical and or chemical

Question 6

DNA damage generated by environmental toxicants: by physical agents

Answer 6

1. ionizing radiation - causes both base damage and sugar damage
2. DNA damage generated by UV radiation

Question 7

DNA damage generated by environmental toxicants: by chemical toxicants

Answer 7

1. alkylation agents - they are electrophilic components with affinity for nucleophilic centers in organic macromolecules, nucleophilic centers in DNA are the most reactive to alkylating agents
2. cross-link agents- cisplatin and anticancer drugs is a cross-link agents also psoralen is
3. chemical toxicants - display their toxic effects through metabolizing into electrophilic reactants