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

Hint: Amino acids are organic molecules containing an amino group and a carboxylic group. The side chain is specific for each amino acid. Amino acids are the building blocks of proteins and enzymes. In the human body,20 amino acids are present. Amines are used for the synthesis of hormones, neurotransmitters, also nitrogen-containing compounds.

Complete step-by-step answer:
The general representation of the amino acid is given as follows:

Here, R represents the side chain that is specific for each amino acid and decides the identity of the amino acids.In alpha-amino acids, the carboxyl group attached to the carbon is alpha carbon known as alpha carbon. Tryptophan is the alpha-amino acid having a side chain of indole.
The structure of the tryptophan is as follows:

Thyroxine and Triiodothyronine are the hormones secreted by the thyroid gland. These are synthesized using the precursor thyroglobulin. Therefore, option (A) Thyroxine and Triiodothyronine is the incorrect answer to the given question.

Now, estrogen and progesterone are the important hormones present in the female body. Testosterone and androstenedione are used precursors for the synthesis of the estrogen while progesterone is synthesized from pregnenolone, a derivative of cholesterol. Therefore, option (B) is an incorrect answer.

Cortisol and Cortisol are steroid hormones. Cholesterol is the precursor used for the synthesis of cortisol and Cortisone hence, option(C) is the incorrect answer for the question.

Melatonin and Serotonin are the neurotransmitters that are synthesized from the amino acid Tryptophan. Therefore, option (D) is the correct answer to the given question.

Note: Amino acids are widely used for the synthesis of proteins, enzymes, hormones, etc. Tryptophan is one of the alpha-amino acids used as a precursor for the synthesis of hormones.