Oxidative Phosphorylation

Question 1

Oligomycin

Answer 1

drug that binds to the stalk of the ATP synthetase, closes the H channel and prevents reentry of the protons into the mitochondrial matrix and prevent phosphorylation of ADP to ATP. ETC shuts down

Question 2

Uncoupling of Ox Phos Proteins

Answer 2

Occurs in the inner mitochondrial membrane of mammals including humans. creates a proton leak which allows protons to re enter the matrix without energy being captured as ATP. Energy is released as heat which is non shivering thermogenesis. There is NO ATP made which diffuses the proton gradient.

Question 3

Synthetic Uncouplers

Answer 3

Example 2,4 Dinitrophenol & FCCP –> Aspirin
Increase the permeability of the inner mitochondrial membrane to protons. Through a lipophillic proton carrier that readilhy diffuses aross the membrane. This causes the electron transport at a rapid rate without establishing a proton gradient. Weak lipophillic acids break the membrane.

Question 4

Chemiosmotic hypothesis

Answer 4

Proposed by Peter Mitchell in 1961
Free energy of E- transport is conserved by pumping H+ from the mitochondrial matrix to the intermembrane space so as to create an electrochemical H+ gradient across the inner mitochondrial membrane. The electrochemical potential of this gradient is harnessed to synthesize ATP.

Question 5

Inner mitochondrial membrane

Answer 5

ox phos requires an intact inner mitochondrial membrane. It is impermeable to ions. Free diffusion would discharge an electrochemical gradient.