Question

In the presence of uncouplers, which of the following occurs?

a) Increased ATP synthesis
b) Decreased ATP synthesis
c) Enhanced electron transport
d) Stabilization of oxidative phosphorylation

Answer 1

In the presence of uncouplers, there is a decreased ATP synthesis as uncouplers allow protons to bypass ATP synthase, dissipating the energy as heat instead of producing ATP.

Step-by-step explanation:

In the presence of uncouplers, decreased ATP synthesis occurs. Uncouplers are substances that disrupt the process of oxidative phosphorylation, which is the final stage of cellular respiration where most ATP is generated. They do this by allowing protons to re-enter the mitochondrial matrix without passing through ATP synthase, which is the enzyme that would normally use this proton flow to synthesize ATP. This proton flow is part of the electrochemical gradient built up by the electron transport chain (ETC). While the ETC continues to operate, uncouplers make it ineffective at producing ATP, and thus the energy is released as heat instead of being captured in the form of ATP. Examples of uncouplers include 2,4-dinitrophenol and dicumarol.