Answer Happy

7) Often aerobic cellular respiration isn't 100% efficient, meaning it doesn't always produce the maximum amount of ATP per glucose. The reason for this is the uncoupling of the ETC and chemiosmosis. The energy released through the oxidation of NADH and FADH, is still used to pump H* ions into the intermembrane space and build up an electrochemical proton gradient. However, the H' ions pass back across the inner membrane without going through ATP synthase, which results in the energy from the electrochemical proton gradient being lost as thermal energy and not used to synthesize ATP. One way uncoupling is achieved is through uncoupling proteins (facilitated transport proteins) found in the inner mitochondrial membrane that provide an alternate pathway (instead of ATP synthase) for H to pass back into the matrix. a) Brown adipose fat found in hibernating animals contain mitochondria that have a high percentage of uncoupling proteins. Why do you think this is? [1] b) In the 1930's, a diet company produced a drug called DNP (2,4-dinitrophenol) which caused channels throughout the inner mitochondrial membrane that allowed ions, including H', to leak. Why do you think this drug was successful for making people lose weight? [1] c) DNP was discontinued after only a few years of use due to the harmful side effects. Any ideas as to what side effect(s) people who were taking this drug were experiencing? [1]