What is a proton pump?
In: Biology
Chemicals in general move from areas of high concentration to low concentration. This is bad if you need a certain chemical to *always* be at a high concentration in a particular spot in order for something to work.
H+ ions, sometimes called “protons” because that’s all that’s left when you remove an electron from hydrogen*, are one such chemical that need to be constantly kept at high concentration in certain places. For example, your stomach, so your stomach fluid always stays acidic. Or inside** your mitochrondria, where they’re used to power ATP synthase to create ATP.
So, proteins exist that force H+ ions into areas that already have a ton of H+ ions, the opposite direction they *want* to go (*against* the high -> low concentration gradient), because unless you’re constantly forcing them to go there, they’ll eventually go somewhere else, and then things break. Proteins that move H+ against the gradient are called “proton pumps”.
(* This technically isn’t true, you can’t just have a single proton chilling on its own like that. Technically you’re transferring a proton between different water molecules, from an H3O+ molecule onto an H2O molecule, onto another H2O molecule, onto another H2O molecule, onto another H2O molecule, etc.)
(** Mitochondria technically have two different “layers” of “inside”. The place where H+ needs to accumulate is in the outermost inside, called the “intermembrane space”.)
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