Question

The amino acid tryptophan is the precursor for the synthesis of

• A. Cortisol and cortisone
• B. Estrogen and progesterone
• C. Thyroxine and triiodothyronine
• D. Melatonin and serotonin

Answer 1

The correct option is D

Melatonin and serotonin

The correct option is D.

Explanation of the correct option

1. Amino acid precursor tryptophan acts as a precursor for the synthesis of both melatonin and serotonin.
2. These are neurotransmitters.
3. It also helps in the generation of antipellagra vitamins and nicotinic acid.
4. Its products influences many bodily functions like sleep, mood, and behavior.

Explanation of the incorrect option

Option A:

1. The main precursor for cortisone is cholesterol.
2. These are the glucocorticoid hormones.
3. Cortisone is the man-made or synthetic version of cortisol.
4. They help in managing pain, swelling, and joint swelling.

Option B:

1. Pregnenolone is the pre-cursor of steroid hormones like estrogen and progesterone.
2. These hormones are released in the ovary and help in maintaining the ovarian and menstrual cycle.
3. These help in pregnancy and the maintenance of the fetus inside the womb.

Option C:

1. Thyroxine is produced by thyroid gland and its precursor is thyroglobulin whereas the precursor of triiodothyronine is thyroxine.
2. These hormones help in maintaining body metabolism, weight regulation, and nail health and form an important part of the endocrine system.

Final answer: The amino acid tryptophan is the precursor for the synthesis of melatonin and serotonin.