Brown fat cells produce a protein called thermogenin in their mitochondrial inner membrane. Thermogenin is a channel for facilitated transport of protons across the membrane. What will occur in the brown fat cells when they produce thermogenin?

AATP synthesis and heat generation will both increase.
BATP synthesis will increase, and heat generation will decrease.
CATP synthesis will decrease, and heat generation will increase.
DATP synthesis and heat generation will both decrease.
EATP synthesis and heat generation will stay the same.

The energy for ATPs synthesis in the mitochondria is generated by the Proton Motive Force (PMF), which pumps protons across the intramembrane ;to set up electrochemical gradient for protons between the matrix and intramemebranes.

The energy generated with the influx of protons down their electrochemical gradients into the matrix is used for ATPs synthesis by the enzyme ATPase synthase.

Thermogenin however increases the permeability of inner mitochondria membrane to protons. Therefore the pumped protons in the intramemebranes leaked back into the mitochondria matrix,thus reducing the electrochemical gradient, inhibiting chemiosmosis, and therefore the energy for synthesis of ATPs by ATPase synthase enzyme in oxidation phosphorylation.

Therefore these uncoupling protein reduces the proton gradient meant for ATP synthesis.However because of the ability to generate heat in the body as non -shivering mechanism of heat generation, thermogenin will increase heat in the brown fat cells.

Explanation: