Proteins

• proteins contain the elements C, H, O and N
• The building blocks are called amino acids, which can be bonded together by a peptide bond
• The main uses for proteins are: structural proteins (bones, hair, nails), transport proteins (haemoglobin) and enzymes (protein catalysts)
• Essential amino acids are 8 (possibly 9) amino acids that cannot be produced by the body and must be obtained from the diet
• Complete proteins (animal proteins) contain the full range of amino acids
• Incomplete proteins (plant proteins) contain low levels of one or more essential amino acids
• Foods rich in protein include lean meats, fish and poultry