lecture 33 - oxidative phosphorylation Flashcards
What are the 2 energetic gradients across the inner mitochondrial membrane as a result of the proton gradient created by the ETC?
A chemical/pH gradient, an electrical gradient
What is the pH/chemical gradient across the inner mitochondrial membrane a result of?
Different H+ concentration on either side of the membrane due to the ETC
What is the electrical gradient across the inner mitochondrial membrane a result of?
A charge difference across the membrane - intermembrane space is positive, matrix if negative
What is the name for the electrochemical gradient across the inner mitochondrial membrane?
The proton-motive force (pmf)
What does the proton motive force drive?
ATP synthesis
What is the relative pH in the intermembrane space of the mitochondria?
low PH, due to increased [H+]
What is the relative pH in the mitochondrial matrix?
High pH, due to protons being pumped out and therefore a low [H+]
What is a bacteriorhodopsin?
A light induced proton pump that uses energy from light to make a proton gradient across a lipid vesicle. This facilities ATP synthase prodcution of ATP
What is the impact of DNP on oxidative phosphorylation?
Shuttles H+ back from inter-membrane space to the matrix, dissipating the proton gradient and preventing ATP synthesis. Energy builds up and is dissipated as heat
What are the 2 parts of ATP synthase?
F1 and FO
Where is F1 of F1FO-ATP synthase found?
In the mitochondrial matrix
Where is F1 of F1FO-ATP synthase found?
In the inner mitochondrial membrane
What are the 2 types of subunits in ATP synthase, as characteristed by their ability to turn?
Rotor and stator subunits
What components of ATP synthase are rotor subunits?
c subunits, gamma stalk, epsilon
What components of ATP synthase are stator subunits?
a,b, alpha and beta subunits
What drives rotor movement in ATP synthase?
Proton flow over the c subunits
What does rotor movement cause in ATP synthase?
Conformational changes in the stator that drive ATP synthesis
What are the 3 conformational positions of the alpha and beta subunits of F1 of ATP synthase?
O (open), L (loose), T (tight)
What happens to alpha/beta subunits in the open (O) state in ATP synthase?
Release or binding of ADP and Pi
What happens to alpha/beta subunits in the loose (L) state in ATP synthase?
Holds ADP and Pi in preparation for catalysis
What happens to alpha/beta subunits in the tight (T) state in ATP synthase?
allows for ATP formation - catalysis of phosphorylation of ADP to ATP
What causes conformational changes in each dimer of alpha and beta subunits in ATP synthase?
The turning of the rotor (via the gamma stalk)
How many protons produce 1 ATP in ATP synthase?
4 protons
How many ATP does an NADH entering the ETC lead to, by pumping 10 protons?
2.5 ATP
How many ATP does an FADH2 entering the ETC lead to, by pumping 6 protons?
1.5 ATP
