Lecture 30 Flashcards
What is oxidative phosphorylation?
The coupled process of the electron transport chain and ATP-synthase
What is the ETC and ATP-synthase coupled by?
A proton gradient
What is the proton-motive force (pmf)?
The proton gradient across the inner mitochondrial membrane
What does the pmf result in?
Two energetic gradients; chemical due to different [H+] and electrical due to different charges (an electrochemical gradient)
Where is the [H+] the highest?
Intermembrane space
How was it determined that the [H+] gradient was essential for ATP produciton?
Treating mitochondrial with mild detergents to remove the outer membrane, ETC still works but no gradient is formed and no ATP is made
What is the artificial liposome experiment and what did it show?
Bacteriorhodosime is a light-inducible proton pump that generates a [H+] gradient. When light is on, ATP is generated. Showing ETC is not required for ATP synthesis
What is DNP?
An uncoupler that shuttles H+ from the intermembrane space to the matrix, thus dissipating the proton gradient
What happens if you take DNP as a weight loss supplement?
Fuel molecules break down through the ETC however no [H+] gradient is formed. This causes the body to increase the rate of breakdown of fuel molecules. As the energy in the gradient must go somewhere, it is converted to heat
What is F1Fo-ATP synthase?
A key enzyme in cellular energy conversion
Where is F1 located?
In the mitochondrial matrix
Where is Fo located?
In the IMM
How does F1Fo-ATP synthase work?
Rotor subunits turn, stator subunits are stationary, and proton flow drives the rotational movement causing conformational changes between the alpha-beta pairs in the stator that drive ATP synthesis
What is the O conformation?
Open; ATP is released, ADP and Pi binding occurs
What is the L conformation?
Loose; ADP and Pi are held in preparation for catalysis
