A macromolecule is a large, complex molecule that is essential for various biological functions. These molecules are typically made up of smaller units called monomers, which bond together to form long chains. Common types of macromolecules include proteins, nucleic acids, carbohydrates, and lipids. Each type plays a crucial role in the structure and function of living organisms. Macromolecules are vital for processes such as energy storage, genetic information transfer, and cellular structure. For example, proteins are made of amino acids and are involved in nearly every cellular function, while nucleic acids like DNA store and transmit genetic information.