Question

How does uncoupling the electron transport chain from ATP synthesis cause thermogenesis? Describe how the two processes and how they are coupled. Describe one way that they can become uncoupled.

Answer 1

a)Uncoupling make the mitochondrial membrane leaky. The proton gradient set up during the electron transport chain is used to produce ATP by pumping protons though the ATP synthase in the mitochondrial membrane. Uncoupling proteins present in the mitochondrial membrane allow the protons to pass through from the internmembrane space into the matrix without passing through the ATP synthase. The energy obtained from this proton transport is used to generate heat, a process knows as thermogenesis.

b) The breakdown of glucose during glycolysis and TCA cycle produces electron carriers NADH2 and FADH2. These take part in the elecron transport chain,which function to pump protons from the matrix to the intermembrane space. Thus, a proton gradient is created across the inner mitochondrial membrane. The protons then pass back to the matrix via the protien ATP synthase, which uses the energy generated from protn transfer to generate ATP.

c) Uncoupling proteins present in the inner mitochondrial membrane can uncouple the proton gradient from ATP synthesis process.