by Jose Juan Gutierrez

Created on: April 09, 2011   Last Updated: April 10, 2011

What are amino acids?

Amino acids are nitrogen containing organic molecules that can join together in chains called (poly-peptides) and form complex proteins. There are 20 basic amino acids of which 8 are essential (they must be obtained from food), and 12 are non-essential (the body produces them). Amino acids are necessary for human metabolism, and for maintaining the body functioning in optimum condition.

Amino acids are organic compounds made of carbon, hydrogen, oxygen, and nitrogen, which make up long polymer chains, which can range from a few to as many as three thousand or more amino acids. A central carbon atom joins together to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (-H), and an organic side group called (-R). It is this side group which gives the protein its different shape and functional chemical properties.

Amino acids join together in long chains by chemically reacting together, forming bonds (peptide bonds) between a carboxyl group and an amino group. Groups of only two amino acids are called dipeptides, whereas three amino acids joined together are known as tripeptides, but if there are more than ten amino acids joined in a chain, then they´re called polypeptides. Fifty or more amino acids in a chain are known as proteins.

All the known proteins in the human body are manufactured by the combination of only 20 amino acids, twelve of which are known as non-essential amino acids, meaning that they are produced naturally inside the human body,  including: arginine, tyrosine, glycine, serine, glutmamic acid, aspartic acid, taurine, cycstine, histidine, proline, alanine, and creatine.

Unlike the non-essential amino acids, which the body is able to create, essential amino acids cannot be manufactured by the body and can only be obtained from external sources, such as food. The essential amino acids are the following: tryptophan, lysine, methionine, phenylalanine, threonine, valine, leucine, and isoleucine.

Just as proteins are formed by the combination of amino acids in long chains (synthesis), they can be broken down to its amino acid form by a chemical process reaction known as (hydrolysis). That´s what occurs in the digestion process when the digestive enzymes in the stomach break down proteins, reducing them to its amino acid condition, and then releasing them into the small intestine, where they are transported into the bloodstream and distributed throughout the human organism.

This is a continuing and endless process in which proteins either taken into the human body via the mouth, then broken down into individual units of amino acids, which later are combined together to form proteins that can be used by cell structures throughout the body.

Resources:

Faqs.org

biologyonline

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