You are referring to a complete protein. Those are generally found in meat, fish, chicken, cheese, yogurt, milk and eggs. Usually, the proteins in plants are usually missing some essential amino acids and therefore, you must mix various plant proteins to get a complete protein. Essential amino acids are those that cannot be synthesized by humans and must be consumed in our diet. A complete protein has those in the correct proportion as well as all the other amino acids needed by the body. Essential amino acids are histidine, valine, tryptophan, threonine, phenylalanine, methionine, lysine, leucine and isoleucine.
Proteins are mainly made up of long chains of 20 amino acid. Our body synthesis 11 amino acid form which 9 are essential amino acid because they must be taken in the form of food.
Source of Proteins: Meat, fish, nuts seed beans and dairy product are the high protein foods. Vegetables, like avocados and sprouts, are also sources of protein.