Proteins are made up of simple units called amino acids. Amino acids absorbed from food are used to synthesize structural proteins (cell membrane proteins), functional proteins (enzymes), protein hormones, carrier protein etc. proteins are essential for growth, development and tissue repair.
Essential amino acids
1. Cannot be synthesized in the animal body
2. It should be obtained from the diet ( therefore called as essential amino acids)
3. Essential amino acids are Arginine (Arg/R), Histidine (His/H), Isoleucine (Ile/I), Leucine (Leu/L), Lysine (Lys/K), Methionine (Met/M), Phenylalanine (Phe/F), Threonine (Thr/T), Tryptophan (Trp/W), and Valine (Val/V).Non-Essential amino acids
1. Can be synthesized in the animal body
2. It can be synthesised in the body (therefore called as non-essential amino acids)
3. Non-essential amino acids are Alanine (Ala/A), Asparagine (Asn/N), Aspartate (Asp/D), Cysteine (Cys/C), Glutamate (Glu/E), Glutamine (Gln/Q), Glycine (Gly/G), Proline (Pro/P), Serine(Ser/S), Tyrosine(Tyr/Y).Extra points:
1. Histidine and Arginine are essential amino acids for infants but not healthy adults.
2. Cysteine and Tyrosine are considered to be semi-essential amino acids. They are required by premature infants and adults who are ill.