Final answer:
Macromolecules are large, essential, and complex molecules made from smaller organic molecules. There are four major classes of biological macromolecules: proteins, carbohydrates, lipids, and nucleic acids, each with distinctive functions and structures determined by the arrangement and bonding of their monomers.
Step-by-step explanation:
Definition of Macromolecules
Macromolecules are large, complex molecules necessary for life, built from smaller organic molecules.
Four Classes of Biological Macromolecules
Proteins: These are molecular machines that perform a wide variety of functions within cells. They are built from amino acids and have complex structures that determine their function.
Carbohydrates: This class of macromolecules serves as a vital energy source for cells and provides structural support in some organisms. They are made up of monosaccharides, disaccharides, and polysaccharides, and are connected by glycosidic bonds formed through dehydration reactions.
Lipids: These are hydrophobic molecules such as fats, oils, and steroids, which function as long-term energy storage, components of cell membranes, and signaling molecules.
Nucleic Acids: These macromolecules, including DNA and RNA, store and transmit genetic information. They are polymers made of nucleotide monomers.
Each class of these biological macromolecules forms through dehydration reactions, where monomers join together releasing a water molecule, and can break down into monomers through hydrolysis reactions, which consume a water molecule for each bond that is broken.