BISC-2 v1

Living things are built from four major classes of biological macromolecules: carbohydrates,

lipids, proteins, and nucleic acids. Carbohydrates are made from monosaccharides

like glucose. When monosaccharides bond, they form disaccharides and polysaccharides

such as starch, glycogen, and cellulose. Functionally, carbohydrates are

used for short-term energy, energy storage, and structure. Lipids are not true

polymers, but they are still large biological molecules. Common lipids include

triglycerides (fats and oils), phospholipids (membranes), and steroids (like cholesterol).

Lipids store long-term energy, form cell membranes, and act as signaling molecules.