Amino acids are molecules that bind through peptide bonds to form proteins . They are made up of carbon chains linked to hydrogen, oxygen, nitrogen and sulfur. They also have a carboxyl group (COOH) and an amine group (NH 2 ), from which its name derives.
There are 20 known amino acids present in the molecules of all proteins existing in nature, which are: alanine, arginine, aspartate, asparagine, cysteine, phenylalanine, glycine, glutamate, glutamine, histidine, isoleucine, leucine, lysine, methionine, proline, serine , tyrosine, threonine, tryptophan and valine.
The plants produce all the amino acids they need from carbon chains of sugar produced by photosynthesis and nitrate removed from the environment. However, animals , including the human species, manufacture only a few amino acids, obtaining the rest from food.
→ Essential and non-essential amino acids
The amino acids that are synthesized by the body are called non-essential . Some amino acids, however, are not formed from others and, therefore, must be obtained through food and are called essentials . There are 10 essential amino acids: arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
Animal foods have a rich amount of protein and, consequently, a wide variety of amino acids, which does not happen in foods of plant origin. However, the combination of rice and beans , for example, has a large amount of protein, since cereals have amino acids that are not present in legumes, making this a nutritious combination.