Question

The amino acid Tryptophan is the precursor for the synthesis of :

• A. Thyroxine and Triiodothyronine
• B. Estrogen and Progesterone
• C. Cortisol and Cortisone
• D. Melatonin and Serotonin

Answer 1

The Correct Option is D

The amino acid Tryptophan is a precursor for several important biochemical compounds in the human body. In this question, we are asked to identify which compounds are synthesized from Tryptophan. Let's analyze the options given:

1. Thyroxine and Triiodothyronine: These are thyroid hormones synthesized from the amino acid Tyrosine, not Tryptophan.
2. Estrogen and Progesterone: These are steroid hormones derived from cholesterol, not from Tryptophan.
3. Cortisol and Cortisone: These glucocorticoids are also derived from cholesterol and not directly from amino acids like Tryptophan.
4. Melatonin and Serotonin: Both of these compounds are indeed synthesized from Tryptophan.

Tryptophan undergoes enzymatic conversion to form 5-Hydroxytryptophan, which is then decarboxylated to produce Serotonin, a neurotransmitter involved in mood regulation. Serotonin can further be acetylated and methylated to form Melatonin, a hormone that regulates sleep-wake cycles.

Thus, the correct answer is: Melatonin and Serotonin.