Terminal Respiration Flashcards
Where is most NADH and FADH2 produced?
In the mitochondrial matrix from CAC and beta-oxidation.
Where else is NADH produced?
In the cytosol from glycolysis.
How is NADH transferred to the mitochondrial matrix?
By the glycerol phosphate shuttle:
How does the glycerol phosphate shuttle work?
electrons from NADH transferred to make G-3-P which crosses outer membrane and transfers electrons to form FADH2.
Why is there an energetic cost to using cytosolic reduced substrates in terminal respiraiton?
FADH2 doesnt pass electons throught he 1st complex so produces less ATP than NADH. Therefore theres a cost to using cytosolic NADH as it becomes FADH2.
Why is ubiquinone used as a dietary supplement?
It reduces free radicals so is used as an antioxidant.
Complex 1:
- Oxidises NADH
- e-‘s passed along Fe-S centres
- Produces ubiquinol (QH2) from matrix H+ ions and e-‘s
- 4H+ ions pumped out the matrix
Complex 2:
- Oxidises FADH2
- Fe-S centres channel e-‘s
- Transfers e-‘s to form ubiquinol
Complex 3:
- Ubiquinol from 1&2 gives up electrons to reduce cytochrome c
- Each QH2 reduces 2 cytochrome c molecules
- Pumps 2 protons out the matrix.
Complex 4:
- e-‘s from cytochrome c channled through Fe-Cu centres
- e-‘s pass to O2 which makes water with matrix protons
- 4 more protons pumped through
How many protons are pumped across for every NADH oxidised?
10 H+ ions or protons
How many protons are pumped across for every FADH2 oxidised?
6 H+ ions of protons
What is Chemiosmosis?
Movement of protons down the electrochemical gradient to produce a proton motive force.
Why is chemiosmosis vectoral?
It has a specific directionality of movement
What generates the electrochemical gradient?
The chemical potential (alkaline inside, acidic outside)
The elecrical potential (-ve inside and +ve outside)
