ETC

Question 1

what happens in the cytochrome c oxidoreductase complex?

Answer 1

dimer of identical monomers in the membrane
each monomer has 3 cytochrome hemes / one FeS cluster
electrons from ubiquinol passed to cytc which carries them to cytc oxidase.

Question 2

Briefly outline the events occurring at cytc oxidase complex.

Answer 2

2 cyt hemes / 3 Cu

accepts electrons, one a time, from cytc and passes to oxygen.

Question 3

Outline the structure / function of complex 1.

Answer 3

Passes electrons from NADH through FMN through 8 Fe-S clusters & to ubiquinone (reduced one electron at a time to ubiquinol).

Question 4

What is the significance of cytochrome c?

Answer 4

once released from Bax pore
interacts with Apaf-1, receuiting / activating caspase-9 –> apoptosome
apoptosome activates caspase-3 –> cleaving / activating CAD (cell fragmentation / death).

Question 5

What is the structure of complex I?

Answer 5

Integral membrane enzyme. 
9 redox cofactors and 44 subunits. 
Has a;
matrix arm
membrane arm
8 Fe-S centres 
FMN flavoprotein.

Question 6

What is the structure of complex III?

Answer 6

Membrane protein (can be called cytochrome bc1 complex) 
Dimer of identical monomers. 
Each monomer has 11 subunits including 
cyt b with 2 heme groups.
Rieske Fe-S protein (Fe2S2) 
CytC1 with heme gp.

Question 7

what are cytochromes?

Answer 7

compounds tightly bound to haem gps that carry one electron.

Question 8

What is the structure of complex IV?

Answer 8

14 protein subunits 
2 catalytic subunits 
2 haems - cyt a3 
cyt a3 
2 copper centres CuA CuB