Oxidative Phosphorylation and Chemiosmotic Coupling

coupling sites

reactions along the electron transport pathway with enough energy to synthesize ATP (that could have catalyzed substrate-level phosphorylation)

“Uncoupling” of oxidative phosphorylation

usually all of the H+s translocated across the inner mitochondrial membrane are used by ATP synthase for ATP synthesis.

but exceptions:

Dinitrophenol is very hydrophobic and acidic so no ATP synthesis occurs

New-born infants, hibernating mammals, and sometimes plants express an uncoupling protein.

Brown adipose tissue

maintain body temp during hibernation

uncouples respiration and phosphorylation to maintain body temperature

Fatty acids are broken down to Acetyl-CoA which enters the TCA cycle and generating NADH and FADH2

The electron transport chain pumps H+ across the membrane But energy is dissipated by uncoupling protein-1 (UCP1), and given off as heat

how does brown adipose tissue maintain body temp?

Neurepinephrine (NE) triggers triglyceride (TG, fatty acid) breakdown