Macromolecules September 16th/17th, 2008

Many of the molecules in living cells are so large that they are known as macromolecules, which means “giant molecules.” Macromolecules are made from thousands or even hundreds of thousands of smaller molecules.

Monomers vs. Polymers Macromolecules are formed by a process known as polymerization, in which large compounds are built by joining smaller ones together – like a puzzle. The smaller units are called monomers. The larger units they create are called polymers.

The four major groups of macromolecules are carbohydrates, lipids, nucleic acids, and proteins.

Reflection What does macromolecule mean? Use an analogy to explain monomers and polymers. What is polymerization? What are the four different types of monomers?

Carbohydrates Living things use carbohydrates as their main source of energy. Carbohydrates are made up of carbon, hydrogen, and oxygen.

The monomers of carbohydrates are called monosaccharides (single sugars). Glucose is an example. The polymers of carbohydrates are called polysaccharides (many sugars). Starch and glycogen are examples.

Lipids Lipids can be used to store energy. Some lipids are important parts of biological membranes and waterproof coverings (the cell membrane for example) . Cell Membrane Lipid

The monomers of lipids are Glycerol and Fatty Acids.

Nucleic Acids Nucleic acids are found in your DNA and RNA. They are the molecules that store and transmit hereditary, or genetic, information. Nucleic acids contain hydrogen, oxygen, nitrogen, carbon, and phosphorous.

Nucleic acids are polymers made up of individual monomers known as nucleotides. Nucleotides consist of three parts: a 5-carbon sugar, a phosphate group, and a nitrogen base.

Proteins Some proteins help to carry out chemical reactions and regulate cell processes. Some are used to form bones and muscle. Other transport substances into our out the cells or help to fight disease. Proteins are macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen.

The monomers of proteins are called amino acids. All amino acids have an amino group (NH2) at one and, and a carboxyl group (COOH) on the other end. Examples of proteins are Hemoglobin, Albumin, Collagen, and Keratin

Amino Acids