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

1 Answer
Jan 7, 2018

Answer:

Here's my understanding of the mechanism.

Explanation:

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

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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.