Percentage composition of fibroin and sericin in silk is

Options

A. `30 : 90`
B. `50 : 40`
C. `40 : 60`
D. `80 : 20`

Answer

To determine the percentage composition of fibroin and sericin in silk, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components of Silk**: Silk is primarily composed of two proteins: fibroin and sericin. Fibroin is the main structural protein, while sericin acts as a gum that holds the fibroin fibers together.

2. **Identify the Percentage Composition**: According to the information available, the percentage composition of silk by weight is approximately:
- Fibroin: 75% to 80%
- Sericin: 17% to 25%

3. **Determine the Average Ratios**: For a more precise understanding:
- If we take an average, fibroin is about 80% and sericin is about 20%. This is a common approximation used in many references.

4. **Conclusion**: Based on the above information, we can conclude that the percentage composition of fibroin in silk is approximately 80%, and the percentage composition of sericin is approximately 20%.

5. **Final Answer**: Therefore, the correct answer to the question is:
- Fibroin: 80%
- Sericin: 20%