Please answer question c In normal mitochondria the rate of electron transfer is
ID: 269001 • Letter: P
Question
Please answer question c
In normal mitochondria the rate of electron transfer is tightly coupled to the demand for ATP. When the rate of use of ATP is relatively low, the rate of electron transfer is low. When demand for ATP increases electron-transfer rate increase. Under these conditions of tight coupling, the number of ATP molecules produced per atom of oxygen consumed when NADH is the electron dono - the PIO ratio is about 2.5. 0 NO, NO, 2,4 dinitrophenol (cytoplasm) a) Illustrate above then summarize below how 2,4-dinitrophenol works with the structure shown and what you know of membrane structure. (10 points) b) The uncoupler 2,4-dinitrophenol was once prescribed as a weight-reducing drug. How could this agent, in principle, serve as a weight-reducing aid? Include what happens to the P/O ratio in your explanation for additional credit. (5 points) c) Uncoupling agents are no longer prescribed, because some deaths occurred following their use. Why might the ingestion of uncouplers lead to death? (5 points)Explanation / Answer
Uncouplers such DNP uncouple the electron transport from the oxidative phosphorylation. They were initially prescribed for weight reduction.
However, they are dangerous for two reasons.
i. Uncoupling produces heat which increases the body temperature which may cause other complications
ii. There is no production of ATP for normal, physiological needs.
iii. Since there is no ATP production, the body mobilizes reserve food materials leading to weakness.
20-50 mg/kg of DNP can cause death in humans.
Due to the health complications, the use of DNP was discontinued in the US in 1938.