Question

Question 5 Speaking of mitochondria. Get your cell biology textbook and review how mitochondria generate ATP. Then consider - some researchers though they had found a wonder diet drug when they discovered molecules that increased the basal metabolic rate by allowing protons to leak across the inner mitochondrial membrane.

A) Describe how these drugs would cause an increase in the basal metabolic rate (that is, the cells are burning more ‘food’ but the organism isn’t doing more ‘work’).

B) What might be negative side effects of this treatment.

Answer 1

A) this weight reducing drug is 2, 4 DNP ( 2, 4 dinitro phenol) .

This drug is uncoupler , uncoupled are those which uncouple oxidation and phosphorylation. In ETC during oxidation of reducing equivalents ( NADH and FADH2) energy is released at some complex. This energy is used to pump protons in to intermembrane space and generate proton motive force. This PMF is actually responsible for generation of ATP. When these protons enter through complex V , it leads to generation of ATP.

2, 4 DNP is permeable to inner mitochondrial membrane, and act as a proton carrier. So this tranport H ions in to mitochondria matrix from inter membrane space thus loss of proton gradient. And with out proton gradient there will be no ATP . So here oxidation takes place but there is no generation of ATP. Energy stored in form of PMF is list in form of heat. So actually food is metabolized without generation of ATP , and released heat increase the basal metabolic rate.

B) DNP has high acute toxicity.

Acute toxicity of DNP ---  increased BMR (basal metabolic rate), nausea, sweating, nausea,  dizziness, headache, and loss of weight.

Chronic oral exposure to DNP -- cataracts and skin lesions and  effects on central nervous system, bone marrow and cardiovascular system