Macromolecules

Knowing what macromolecules are is an important step to understanding how nutrients are absorbed and used by cells. The term macromolecules simply means large molecules and refers to four different compounds, carbohydrates, lipids, proteins, and nucleic acids. Each of these has a unique structure and function. Let's talk about carbohydrates first.

All carbohydrates are composed of carbon, hydrogen, and oxygen. Those with simple structures are called monosaccharides or sugars. Monosaccharides can join to form more complex carbohydrate chains called polysaccharides or starch. Starch's normal form resembles a coiled spring because of the bond angles in the polymer chain.

The next type of macromolecule we'll discuss is protein. Proteins are built from chains of amino acids, organic compounds that each have an amino group or N-terminal at one end and a carboxyl group, or C-terminal at the other. There are 20 standard amino acids and while they all have a similar base structure, each has a unique side chain known as the R-group. Different amino acids can link together to form a chain connected by peptide bonds and create a protein.

The final class of macromolecules we will examine is lip