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Name: Zachary
Status: Student
Age: 15
Location: N/A
Country: N/A
Date: N/A 

I have asked this before, but I did not see the response anywhere on the website or in my email. Are all living organisms made up of only 20 amino acids?

There are 20 basic amino acids but there are some other unusual amino acids in a variety of organisms...these amino acids to my knowledge are not usually coded for in the genetic code.


Animals and plants use only 20 amino acids. All but 8 are manufactured in the human body. The 8 are the essential amino acids needed in diet.

Steve Sample

On this planet, yes, there are only 20 naturally occurring amino acids. But one interesting bit of trivia -- the product you know as Nutrasweet is really a synthetic (chemically produced) compound that can technically be defined as an amino acid, though it is not a naturally occurring one, so it is not used in making any proteins.

Christine Ticknor, Ph.D.
S Case Western Reserve University

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