Give example of tertiary structures.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Tertiary Structure**: The tertiary structure of a protein refers to its three-dimensional shape, which is crucial for its function. This structure is formed by the folding and interactions of the polypeptide chain, which is made up of amino acids linked by peptide bonds.

2. **Types of Proteins**: Proteins can be categorized based on their tertiary structure into two main types: fibrous proteins and globular proteins.

3. **Example of Fibrous Protein**: An example of a fibrous protein is **alpha keratin**. This protein has a long, thread-like structure and is commonly found in hair, nails, and the outer layer of skin. Its structure is rope-like, providing strength and resilience.

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