L17- Oxidative phosphorylation Flashcards
(30 cards)
What is made in the citric acid cycle that is then oxidized in oxidative phosphorylation?
NADH and ubiquinol (QH2)
What is formed in oxidative phosphorylation when they are oxidized?
NADH and ubiquinol (QH2)
What happens in summary in the ETC?
Oxidation energy is used to transport protons, creating a proton gradient.
What does ATP synthase use?
The proton gradient energy produce ATP
When do glycolysis and citric acid cycle happen?
Glycolysis- cytoplasm
Citric acid cycle- matrix of mitochondria
(apart from the one enzyme in the membrane)
Where is the movement of protons?
Across the inner membrane
What must the inner membrane be so that we can generate energy?
Impermeable by protons and intact
What happens to the pH inside the mitochondria as the ETC happens?
The pH rises as H+ (protons) get transported out
What’s created across the inner membrane?
A small charge difference, as +ve charge is being transported out
How many complexes are in the ETC?
4 Electron transport complexes I-IV. Then ATP synthase at the end.
Who came up with the chemiosmotic theory? what is it?
Electron transfer is coupled to proton movement across a membrane. Gradient buils up and sevres as an energy reservois during ATP formation.
Peter Mitchell in the 1960s
Which experiment convinces peter mitchell?
O2 was only consumed when ADP was added. When 24-DNP was added, it could move protons across the membrane, so didn;t need ATP
WHat is protonmotive force? (∆p)
The energy (driving potential) of the proton conc. gradient.
In the negative E’ (v) side of the ETC, what is favourable and unfavourable?
Conversion of NADH to form NAD+. Extraction of elctrons. Reduction is unfavourable.
Which reaction is favoured at the +ve E’ (v) side?
Conversion of O2 and H+ to water is favourable
Which complex in the ETC is involved in the citric acid cycle?
Only complex II!!!
succinate-ubiquinone oxidoreductase. converting succinae to fumarate
What can ubiquinone bind to?
The first 3 complexes in the ETC chain
What redox does ubiquinone do with the complexes?
It accepts electrons from the first 2 complexes. It gives electrons to complex III.
What are the mobile electron carriers?
Cytochrome C and ubiquinone
WHere does cytochrome C accept or donate its electrons?
When bound to complex III it accepts electrons.
When bound to complex IV, it donates electrons
Where do the elctrons come from at the start of the ETC?
Either NADH and succinate
WHat happens to flavin coenzymes in the ETC?
They’re reduced.
In complex I- FMN–> FMNH2
complex II- FAD —> FADH2
Then they give electron one at a time to the mobile coenzymes
How many electrons needed to convert ubiquinone (Q) to ubiquinol (QH2)?
2 electrons
HOw many protons are translocated per 2 electrons transferred?
(in complex I)
4 H+ per 2 electrons
