Keratin in skin , hair, nails and wool is a

Options

A. Fibrous protein
B. `alpha`-helix type
C. Globular protein
D. None of these

Answer

To determine the nature of keratin found in skin, hair, nails, and wool, we can analyze the characteristics and classifications of proteins. Here’s a step-by-step solution:

### Step 1: Identify the Type of Protein
Keratin is a protein found in various parts of the body, including skin, hair, nails, and wool. The first step is to classify keratin based on its structure.

**Hint:** Consider the physical characteristics of keratin and how it is organized at the molecular level.

### Step 2: Determine if Keratin is Fibrous or Globular
Keratin is known to be a fibrous protein. Fibrous proteins are characterized by their elongated, thread-like structures, which allow them to form fibers. This is different from globular proteins, which are more spherical and compact.

**Hint:** Think about the structural properties of proteins and how they relate to their functions.

### Step 3: Analyze the Structure of Keratin
Keratin has an alpha helix structure, which is a common secondary structure in proteins. This structure contributes to the strength and elasticity of keratin, making it suitable for its role in providing support and protection in skin, hair, nails, and wool.

**Hint:** Recall the different types of secondary structures in proteins and their significance.

### Step 4: Consider the Properties of Fibrous Proteins
Fibrous proteins, including keratin, are generally insoluble in water due to the strong intermolecular forces (like hydrogen bonds and disulfide bonds) that hold their polypeptide chains together. This property is essential for their structural role in various biological tissues.

**Hint:** Reflect on the solubility of proteins and how it relates to their structure and function.

### Conclusion
Based on the analysis, keratin in skin, hair, nails, and wool is classified as a **fibrous protein** with an **alpha helix type structure**. Therefore, the correct answer is both options: fibrous protein and alpha helix type.

### Final Answer
Keratin in skin, hair, nails, and wool is a **fibrous protein** and has an **alpha helix type structure**.