Polymers (Basic science review)

1. What is a polymer?
2. Polymers in biology
3. Proteins
4. DNA
5. Carbohydrates
6. Hydrocarbons
7. Other Polymers

What is a polymer?

• A polymer is a large molecule made up of similar small molecules.
• The small molecules are called monomers.
• Often the monomers in a polymer are identical, but sometimes the monomers are different types of molecules in the same class.

Polymers in biology

• There are 4 classes on polymers that are essential to biology.

Polymer	Monomer	Uses
Protein	Amino acid	Enzymes and structural proteins
DNA & RNA	Nucleotide	Contains the information for making proteins
Carbohydrate	Monosaccharide	Energy storage
Hydrocarbon	-CH2–	Energy storage, cell membrane structure

Proteins

• There are 20 amino acids that make up all proteins.
• Proteins contain anywhere from a few amino acids to thousands of amino acids.

DNA

• DNA is made of 4 bases: adenine, guanine, cytosine, and thymine.
• RNA is also made of 4 bases: adenine, guanine, cytosine and uracil.

There are many ways to represent the DNA molecule.

Carbohydrates

• Simple sugars are called monosaccharides. These include glucose, fructose, galactose, and ribose (among others).

• Two monosaccharides can join to form a disaccharide. Common disaccharides include lactose, sucrose, and maltose (among others).
• Monosaccharides can also join to form polysaccharides, such as starch, glycogen and cellulose.

Hydrocarbons

• Hydrocarbons typically contain only carbon and hydrogen.
• By adding a carboxyl group (-COOH) at the end, this becomes what is known as a fatty acid.

• Fatty acids can, in turn, be joined together to form a triglyceride.

Other Polymers

Plastics are synthetic polymers. Polyethylene is a typical example of a polymer.