1. Carbohydrates: These are composed of carbon, hydrogen, and oxygen. They serve as a primary energy source for cells and provide structural support in plants (cellulose). Examples include sugars, starches, and cellulose.
2. Lipids (fats and oils): These are also composed of carbon, hydrogen, and oxygen, but with a higher proportion of hydrogen. They function as energy storage, insulation, and components of cell membranes. Examples include triglycerides, phospholipids, and steroids.
3. Proteins: These are made up of amino acids linked together by peptide bonds. They play a vast array of roles in living organisms, including enzymes, structural components, hormones, and antibodies. Examples include enzymes, collagen, insulin, and antibodies.
