Class 11 NEET Biology Chemical Coordination and Integration

(c) : Iodine is needed for the synthesis of T3 and T4. Iodine binds to the tyrosine residues in thyroglobulin, which is then hydrolysed into iodotyrosines that combine to form triiodothyronine (T3) or thyroxine (tetra-iodothyronine or left.T4) Therefore, deficiency of iodine in the diet of a pregnant female will lead to improper synthesis of thyroid hormones in newly borne infant. The deficiency of thyroid hormones in infants causes 'cretinism' whose symptoms are slow heart beat, lower blood pressure, decrease in temperature, stunted growth, low intelligence quotient and abnormal skin.