Final answer:
Among the given options, a proton pump would increase the electrochemical potential across a membrane by actively transporting hydrogen ions and creating a gradient, essential for ATP production.
Step-by-step explanation:
The question asks which of the following would increase the electrochemical potential across a membrane. Among the options provided, a proton pump (C) would actively transport hydrogen ions (H+) across a membrane, which is a process that requires energy and results in the creation of an electrochemical gradient. This gradient is essential for various cellular processes, such as ATP production in mitochondria through oxidative phosphorylation. The options that include channels (A, D, and E) facilitate the diffusion of ions down their electrochemical gradients and do not directly create a gradient.
A sucrose-proton cotransporter (B) might contribute to a gradient if it involves coupling the favorable movement of protons with the transport of another substance against its gradient, but it's not the primary option for increasing potential across a membrane. Therefore, the correct answer is C, a proton pump, and if we consider E (both a proton pump and a potassium channel), the proton pump in this combination is still the component that would increase the potential.