Proteins are absolutely essential to living organisms!

Proteins are polymers constructed from amino acid monomers

Proteins are the most important macromolecule because without them, living things would not exist. Proteins are involved in every aspect of every living thing.

The structure of each protein determines its function.

There are seven major classes of proteins:
1. Structural - Support to cells as cytoskeleton
2. Contractile - Provides movement in muscles/other cells
3. Storage - Sources of amino acids
4. Defense - Antibodies foreign invaders in blood
5. Transport - Hemoglobin which carries oxygen
6. Signaling - Hormones, membrane proteins
7. Enzymes - Regulators of the speed of biochemical reactions

Proteins are made from amino acids linked by peptide bonds

These three groups + a hydrogen atom are bonded to a central carbon atom

Dehydration Synthesis

Through a dehydration reaction, amino acid monomers form dipeptides (2 amino acids) or polypeptides (several to more).