9.3.1 (Exam 2) Oxidative Phosphorylation Flashcards
Oxidative Phosphorylation Forms ATP
What happens in oxidative phosphorylation?
ATP is synthesized by reoxidation of electron carriers in the presence of O₂
What are the two components of oxidative phosphorylation?
Electron transport
Chemiosmosis
What happens in the electron transport chain (ETC)?
Electrons from NADH and FADH₂ pass through the respiratory chain of membrane-associated carriers
Electron flow results in proton concentration gradient across the inner mitochondrial membrane
What happens in chemiosmosis?
Protons flow back across the membrane through a channel protein, ATP synthase, which couples the diffusion with ATP synthesis
Why does the electron transport chain have so many steps?
One reaction → too much energy
In a series of reactions, each releases a small amount of energy that can be captured by an endergonic reaction
Where is the respiratory chain of the ETC located?
The respiratory chain is located in the folded inner mitochondrial membrane
How is energy released in the respiratory chain of the ETC?
Energy is released as electrons are passed between carriers
What are the carriers in the respiratory chain of the ETC?
4 integral membrane proteins (3 transmembrane)
Lipid—Ubiquinone (CoQ10)(Q)
Peripheral protein—Cytochrome c
What is the structure of the mitochondrial membrane?
There is an outer membrane, an intermembrane space, an inner membrane, and then the mitochondrial matrix within the inner membrane
What is the proton-motive force? What is it caused by?
The potential energy created by the electrochemical gradient between the mitochondrial matrix and the intermembrane space
It is caused by the active transport of H+ ions (protons) into the intermembrane space of a mitochondria by actively transporting electrons from higher energy to lower energy states
ATP synthase can also act as ATPase, hydrolyzing ATP to ADP and Pi.
ADP + Pi ⇌ ATP
Why is ATP synthesis favored?
ATP leaves the matrix as soon as it is made, keeping ATP concentration in the matrix low
H+ gradient is maintained by active transport
