Question

Describe the biochemical mechanism throgh which HCl is formed in the stomach(in humans) (?)

Answer 1

Here's my understanding of the mechanism.

Explanation:

Hydrochloric acid is produced by the parietal cells in the stomach.

These cells secrete about 60 mL `"HCl"` per hour at a concentration of
roughly 0.16 mol/L.

This is about `3 × 10^6` times the concentration of `"H"^"+"` ions in blood.

Thus, the secretion of hydrochloric acid depends on active transport.

The key player is a proton pump `bb((1)"` located in the cell membrane.

The dissociation of water within the cell generates `"H"^"+"` and `"OH"^"-"` ions.

The `"OH"^"-"` ions combine with `"CO"_2` to form `"HCO"_3^"-"` and are transported out of the cell by anion exchange for `"Cl"^"-"color(white)(l)bb((2))` .

The `"Cl"^"-"` ions are transported out of the cell by conductance channels `bb((3))`.

The proton pump removes `"H"^"+"` ions from the cell in exchange for `"K"^"+"` ions. This effectively recycles the `"K"^"+"` ions.

The net effect is that one `"H"^"+"` ion and one `"Cl"^"-"` ion leave the cell for each water molecule that dissociates.