Macromolecules are large polymers made up of smaller repeating units called monomers. There are four main types of macromolecules found in living organisms, each built from different monomers:

1. Carbohydrates: Monomers are monosaccharides (simple sugars like glucose, fructose, galactose). These monomers link together to form disaccharides (like sucrose) or polysaccharides (like starch, glycogen, cellulose).

2. Lipids (fats, oils, waxes): Monomers are fatty acids and glycerol. These components combine to form triglycerides, phospholipids, and steroids.

3. Proteins: Monomers are amino acids. These 20 different amino acids link together in various sequences to form long polypeptide chains, which then fold into complex 3D structures.

4. Nucleic Acids: Monomers are nucleotides. These are composed of a sugar, a phosphate group, and a nitrogenous base. DNA and RNA are both nucleic acids.

Therefore, all macromolecules are built upon these fundamental building blocks: monosaccharides, fatty acids, glycerol, amino acids, and nucleotides.