Question

Thermogenin and 2,4-dinitrophenol (DNP) are both uncoupling agents. Thermogenin is found in newborn animals and some adult mammals. DNP was marketed in the 1930s as a diet pill. However, DNP treatment not only resulted in weight loss but also death of the patient.

1.Based on this information, how do uncouplers disrupt electron transport/chemiosmosis?
2.Why do thermogenin and DNP result in such different outcomes when both work via a similar mechanism?

Answer 1

Uncouplers like thermogenin and DNP disrupt mitochondrial ATP production by allowing protons to leak across the membrane, dissipating energy as heat. Thermogenin is temperature-regulated in the body, while unregulated DNP use can cause fatal hyperthermia.

Step-by-step explanation:

Uncouplers such as thermogenin and 2,4-dinitrophenol (DNP) disrupt electron transport and chemiosmosis by making the inner mitochondrial membrane more permeable to protons (H+). This decreases the proton gradient used to power ATP synthase, causing the potential energy to be released as heat instead of being stored in ATP molecules.

Thermogenin and DNP result in different outcomes because thermogenin is naturally regulated by the body and allows for adaptive thermogenesis, particularly in newborns that need to generate heat without shivering. DNP, on the other hand, is not regulated, leading to excessive thermogenesis, potentially causing dangerous hyperthermia and death.