protein structures

Proteins are complex molecules made up of long chains of amino acids. They have four levels of structure: 1. **Primary Structure**: The sequence of amino acids. 2. **Secondary Structure**: Local folding into shapes like spirals (alpha helices) or sheets (beta sheets). 3. **Tertiary Structure**: The overall 3D shape formed by further folding and interactions. 4. **Quaternary Structure**: The assembly of multiple protein chains into a functional unit. These structures are crucial because they determine a protein's function in the body, such as catalyzing reactions, providing structure, or transporting molecules.