Oxidative Phosphorylation

Final aerobic stage of cellular respiration (aka: electron transport chain)

The series of proteins and organic molecules found in the inner membrane of the mitochondria

The electron transport chain

The energy released in the ECT is captured as a:

Proton gradient

What are the two main electron acceptors in the ETC

NAD+ and FAD

How many protons can NAD+ and FAD each accept?

2; NADH+H and FADH2

What is the final electron accepter in the ETC

O2

Name complex I

NADH dehydrogenase

Name complex II

Scuinate dehydrogenase

Name complex III

Cytochrome bc1

Name complex IV

Cytochrome c oxidase

Where does the ETC occur in eukaryotic cells?

Innermitochondrial membrane

Where does the ETC occur in prokaryotic cells?

Plasma membrane

This complex accepts two electrons from NADH+H⁺ and transfer them, through Fe-S clusters, to a lipophylic molecule, ubiquinone (Q), which gets converted to ubiquinol (QH₂)

Complex I or NADH dehydrogenase

This oxidizes succinate to fumarate and transfers both released electrons to FAD, yielding FADH₂

Complex II or succinate dehydrogenase

This accepts electrons from ubiquinol and transfers them to cythocrome c

Complex III or cytochrome bc1

This receives four electrons from cythocrome c and transfers them to O₂

Complex IV or cytochrome c oxidase

Where is H+ transferred from and to?

From the mitochondrial matrix into the intermembrane space

Special protein that transports H+ back into the mitochondrial matrix

ATP synthase

Two main components of APT synthase

1. Intermembrane proton channel (F₀)

2. Catalytic protein complex (F₁) facing the mitochondrial matrix