Cellular trivia ? anyone hmm hmm?

[jkool47]

Ill post a new one when someone gets the right answer=)
humans use 20 diffrent kinds of these building blocks of proteins?

[kolean]

Humans use 20 common AMINO ACIDS as building blocks of protein (though there are close to 100 different amino acids that are observed in proteomics: phosphorylation, glycosylation, acetylation, and hydroxylations of the common amino acids are just a few of the modifications we know of so far).

[kolean]

Too slow, I have a new one:

What is the theory of where the mitochondia/chloroplasts come from?