1. Carbohydrates: These are made up of carbon, hydrogen, and oxygen. They are the primary source of energy for living organisms and also provide structural support. Examples include sugars, starches, and cellulose.

2. Lipids (fats and oils): These are also made up of carbon, hydrogen, and oxygen, but in different proportions than carbohydrates. They are important for energy storage, insulation, and cell membrane structure. Examples include triglycerides, phospholipids, and steroids.

3. Proteins: These are large, complex molecules made up of amino acids. They have a wide variety of functions, including structural support, enzymatic activity, transport, and defense. Examples include enzymes, antibodies, and collagen.

4. Nucleic Acids: These are made up of nucleotides, which are composed of a sugar, a phosphate group, and a nitrogenous base. They carry genetic information and are involved in protein synthesis. Examples include DNA and RNA.