oxygen toxicity Flashcards
1
Q
what is a reactive oxygen species?
A
highly reactive molecules, free radicals and compounds containing O2
2
Q
what do reactive oxygen species contribute to?
A
- aging
- homeostasis (resp burst)
- some cancers
3
Q
what is the respiratory burst?
A
- Occurs in phagocytosis of bacteria
- Central to defence system
- Damages membranes of invading organisms
- Consumes oxygen
4
Q
how do reactive oxygen species damage cells?
A
- OH- attacks specific amino acids
- causes protein fragmentation
- disrupts lipid bilayer by increasing permeability
5
Q
how is H2O2 turned into an OH radical?
A
- by the fenton reaction
- Fe2+ is oxidised to Fe3+
- this gives rise to OH- and a OH radical
6
Q
what is the haber-weiss cycle?
A
4 reactions to produce a OH - and consume a H2O2
7
Q
what 3 enzymes are involved in the defence against reactive oxygen species?
A
- superoxide dismutase
- catalase
- glutathione peroxidase
