Skin pigment melanin is formed from
(a) Tyrosine
(b) Adrenaline
(c) Indole-3-acetic acid
(d) Tryptophan

Options

A. Tyrsine
B. Adrenaline
C. Indole-3-acetic acid
D. Tryptophan

Answer

To determine the correct answer to the question about the formation of the skin pigment melanin, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the precursor or substrate from which the skin pigment melanin is formed.

2. **Identifying Melanin**: Melanin is a pigment responsible for the coloration of skin, hair, and eyes. It is produced by specialized cells called melanocytes.

3. **Role of Melanocytes**: Melanocytes are the cells that synthesize melanin. Within these cells, there are organelles called melanosomes where melanin is produced.

4. **Enzyme Involvement**: The synthesis of melanin is catalyzed by an enzyme known as tyrosinase. This enzyme plays a crucial role in the conversion of substrates into melanin.

5. **Identifying the Substrate**: The primary substrate for the synthesis of melanin is the amino acid tyrosine. Tyrosine is converted into DOPA (dihydroxyphenylalanine) and then further processed to form melanin.

6. **Evaluating the Options**:
- (a) Tyrosine: Correct, as it is the substrate for melanin synthesis.
- (b) Adrenaline: Incorrect, as it is a hormone and not involved in melanin synthesis.
- (c) Indole-3-acetic acid: Incorrect, as it is a plant hormone and not related to melanin.
- (d) Tryptophan: Incorrect, as it is another amino acid but not involved in melanin production.

7. **Conclusion**: Based on the above analysis, the correct answer is (a) Tyrosine.

### Final Answer:
The skin pigment melanin is formed from (a) Tyrosine.

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