Chapter 2

transition

purine for purine, pyrimidine for pyrimidine

transversion

purine for pyrimidine

chromosomal translocation

move piece from 1 chromosome to another

carcinogen

capable of causing cancer

carcinogen methods

covalently modify bases in DNA

cause DNA adducts to form

disrupt DNA 3D structure

DNA damage

change shape of DNA helix, affects how it is packed and read

adducts

DNA-protein cross-linked complexes

translesion repair

DNA polymerase incorporates A into abasic sequence

base excision repair

change in FG changes H bonding, forming bubbles

enzymes surround bubbles → cut out and replace bad nucleotide → ligase

endonuclease, Pol beta, DNA ligase

nucleotide excision repair

thymine dimers → big bubbles

take out chunk

DNA helicase, endonuclease, DNA Pol and DNA ligase

mismatch repair

mismatch recognition → subunit assembly → nick formation and exonuclease recruitment → excision → resynthesis and DNA ligation

homologous recombination

find homologous sequence, form holliday junction

non-homologous end joining

stick it together

alkylating agents

alkylate bases, can cause DNA fragmentation, crosslinking, and inhibit transcription

antimetabolites

competitively inhibit reactions

aromatase inhibitors

inhibit estrogen synthesis

drug resistance mechanisms

modify drug metabolism

increase drug target

stop influx

increase efflux