So as you might intuit, having everything work totally differently doesn't scale so well. So a lot of the chemistry inside cells is strongly standardized. Ok, so the nice thing about standards is that there's a bunch to choose from, and sure there's a lot of times when cells cheat just a smidge (or two, or three).

But... end of day, if you squint just a little, most everything is done with a standard set of amino acids that chain together in standard ways. In some AA's The Amino and Acid groups used to daisy-chain them together dwarf the actual active part! And data is stored using a standard set of 4 ( ok 5, ok... exceptions exist) bases.

(Just to be sure, eg. Hemoglobin does suddenly have an Iron atom in there, but it's still _mostly_ made of standard "lego blocks" == amino acids)