Citrate cycle, respiratory chain & oxidative phosphorylation Flashcards
The citric acid cycle is localised in the…
Mitochondrion
Which enzymes regulate the citric acid cycle?
- Citrate synthetase
- Isocitrate dehydrogenase
Give the energy gain of the citric acid cycle
12 ATP/cycle
Oxidative phosphorylation + respiratory chain is localised in the…
Inner membrane of the mitochondrion
Where is energy derived from for use in the respiratory chain + oxidative phosphorylation?
- Proton motive force supplied to ATP synthase (mitochondria)
- NADH + H+ and FADH produced from:
- Glycolysis
- Fatty acid oxidation
- TCA cycle
- (Acting as electron/hydrogen donors)
Which protein complexes take part in the electron transport chain?
Respiratory complex:
- I
- II
- III
- IV
Respiratory complex I
- NADH dehydrogenase
- NADH + H+ used as the initial H+/electron donor
- Pumps 4 protons from the matrix → IM space
Respiratory complex II
- Succinate dehydrogenase
- Succinate → Fumarate
Cytochromes
Small proteins containing a haem group
Respiratory complex III
- Produces reduced cytochrome c
- Translocation of 4 protons
Respiratory complex IV
- Cytochrome-c oxidase
- Produces water
- Translocation of 2 protons
Chemiosmotic theory
- ATP synthase
- Termed ‘Complex V’
- ADP + P → ATP (Matrix)
Give examples of chemiosmosis inhibitors
- Rotenone
- Malonate
- Antimycin-A
- Cyanide
- Oligomycin
Uncoupling reagents
- Lipid-soluble weak acids
- Function as carriers of H+
- Dissipate H+ electrochemical gradient
- E.g H+ can uncouple dinitrophenol
Uncoupling protein
- Thermogenin
- Functions as an H+ carrier
Name the process
Respiratory chain
H+
- Enzyme
- Reaction
NADH dehydrogenase
- NADH → NAD+ + H+
- Enzyme
- Reaction
Succinate dehydrogenase
- Succinate → Fumarate
- Enzyme
- Reaction
Cytochrome-C oxidase
- 2H+ + 1/2O2 → H2O
ATP synthase
Q
Coenzyme Q (Ubiquinone)
C
Cytochrome-C
