# Chapter Two: Organic Chemistry

### Secondary Structure of Protein

| Secondary structures of proteins are polypeptide chains that form in certain ways to make different shapes which do a specific job. There are two main types of secondary structures. Two fibrous structures the alpha helix, and the beta pleated sheet, which are structural components of the cell. The alpha helix is formed when the polypeptide chains twist into a spiral. This allows all amino acids in the chain to form hydrogen bonds with each other. The hydrogen bond attaches a oxygen molecule to a hydrogen molecule, which allows the helix to hold the spiral shape, and tightly coiled. The spiraling shape makes the alpha helix very strong. An example of an alpha helix structure is fingernails or toenails.

The beta pleated sheet is polypeptide chains running along side each other. It is called the pleated sheet because of the wave like appearance. They are linked together by hydrogen bonds. It allows for more hydrogen bonding by stretching out the polypeptide chain. An example of the beta pleated sheet structure is feathers. |

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