Terminal respiration Flashcards
Describe the electron transport chain
Has 4 complexes, l ll lll lV
Describe complex l
Oxidises NADH
Pass high energy e- to ubiquinone to make ubiquinol (QH2)
Uses Fe-S centres (Redox centres)
Pumps 4H+ to intermembrane space
Describe complex ll
Oxidises FADH2
Pass high energy e- to ubiquinone to make ubiquinol (QH2)
Uses Fe-S centres (Redox centres)
Enzyme (Succinate used in CAC)
Describe complex lll
Takes e- from QH2 passes them to cytochrome c
1 QH2 is oxidised to two reduced cytochrome c
Pumps 4H+ protons into the intermembrane space
Describe complex lV
Takes e- from cytochrome c and passes them to molecular O2
e- go through Fe-Cu centres
Pumps 2H+ protons into the intermembrane space
Describe energy conservation through the chain
Oxidation of NADH, FADH2, ubiquinol and cytochrome c creates proton gradient across inner mitochondrial membrane
What is the function of O2
Converted from O2 to H2O
Protons from step lV are used
O2 is final electron acceptor and allows for proton concentrations to be maintained
What is the proton motive force
Protons outside inner membrane store potential energy
Protons flow down conc. gradient, energy is released (PMF)
Describe ATP synthesis
Protons flow down conc. gradient to mitochondria matrix
ATPase mechanism allows protons to pass through
Flow through ATPase releases energy stored in gradient to convert ADP + Pi to ATP
Describe ATPase
F0 – membrane bound proton conducting unit
10 subunits
Separate subunit connects F0 to F1
F1 – mitochondrial matrix
Catalyst for ATP synthesis
Produces lots of ATP from the proton motive force energy collected by F0
What is the binding change mechanism
Rotation of F0 causes conformational change in F1
Conformation change catalyses ADP + Pi = ATP and release of ATP
What is coupling/uncoupling
If inner mitochondrial membrane becomes permeable to protons, no proton gradient, no ATP and is now uncoupled
Energy from e- passing through terminal respiration releases heat
