Metabolism - Lecture Thirty-Three

Question 1

Proton Motive Force

Answer 1

The proton gradient across the inner mitochondrial membrane results in two energetic gradients

Question 2

Two energy gradients caused by the proton gradient

Answer 2

A chemical gradient or pH gradient as a result of different H+ concentrations on either side of the membrane
An electrical gradient as a result of the charge difference across the membrane (positive in the intermembrane space, negative in the matrix)

Question 3

Uncouplers

Answer 3

Can stop ATP synthesis

Question 4

F1Fo-ATP synthase

Answer 4

F1 is in the matrix

Fo is in the inner mitochondrial membrane

Question 5

How does F1Fo-ATP synthase work?

Answer 5

As a molecular motor where the ‘rotor subunits’ turn, the ‘stator subunits’ do not turn. Proton flow drives rotor movement which causes conformational changes in the stator that drives ATP synthesis

Question 6

O of the rotor

Answer 6

Open - exposed to solution around it, if ATP is made it is released and new substrates can come in

Question 7

T of the rotor

Answer 7

Tight - conformation in alpha-beta subunits is correct to make ATP

Question 8

L of the rotor

Answer 8

Loose - getting ready for catalysis

Question 9

NADH energy accounting

Answer 9

10 protons pumped, 2.5 ATP made

Question 10

FADH2 energy accounting

Answer 10

6 protons pumped, 1.5 ATP made