The amino acid tryptophan is the precursor for the synthesis of
- estrogen and progesterone
- cortisol and cortisone
- melatonin and serotonin
- thyroxine and triiodothyronine.
Answer
(3) melatonin and serotonin
Solution
Tryptophan 5-hydroxytryptophan serotonin melatonin (in the pineal gland).
⇒ Estrogen, progesterone, cortisol and cortisone are steroids (from cholesterol); thyroxine and triiodothyronine are iodinated tyrosine derivatives.
Answer: (3)