Question

What are the essential amino acids? Give examples.

Answer 1

Amino acids can be categorized into essential and non-essential based on the synthesis of those amino acids by the body. Certain amino acids cannot be synthesized by the human body and therefore must be supplied through diets whereas the other amino acids are synthesized within the body.

Complete step by step solution:
-Let's start with the concept of amino acids. Amino acids can be described as the group of organic molecules which consists of an acidic hydroxyl group ($-COOH$), a basic amino group ($-N{{H}_{2}}$) and an organic R group or side chain which is unique for each amino acids.
-Through the polymerization of amino acids with the formation of a peptide bond, proteins are formed. The combination of amino acids which is going to make a protein is directed by the genetic material. There are basically twenty amino acids that makeup proteins and they almost have a similar structure with a difference of R (side chain) attached.
-As we mentioned there are mainly twenty amino acids and out of these the human body can synthesize 11 amino acids and the remaining nine amino acids cannot be synthesized by the body and those amino acids must be acquired through our diet. Those amino acids which need to be obtained from the diet are known as essential amino acids.
-The nine essential amino acids are valine, phenylalanine, lysine, histidine, leucine, isoleucine, methionine, threonine and tryptophan and all of these amino acids must be obtained from various dietary sources. These dietary sources are generally classified into 'complete proteins' and 'incomplete proteins'.
-Complete proteins are the foods in which all the nine essential amino acids are present and the examples are eggs, meat, seafood, dairy products etc. In the case of incomplete proteins, only some of the essential acids are present and the examples are grains, beans, nuts etc.
-These essential amino acids have vital functions such as tissue repair, nutrient absorption and protein synthesis.

Note: It should be noted that along with the essential and non-essential amino acids, there is another class of amino acids known as conditionally essential amino acids. Under specific conditions only, these amino acids become essential. For example, when a body is fighting with cancer, it cannot meet the demands of the non-essential amino acid arginine and hence it needs to be supplied through our diets.