We've already learned about polypeptides and proteins being built from amino acids.

We can also build up natural polymers from glucose - simple sugar.

Joining two Glucose molecules together can make a more complicated sugar - Sucrose.

Joining many of them can make starch.

We can show the link between molecules as below - but you don't need to learn the structure.

If we join them slightly differently we get cellulose.

Again, we don't need to learn the difference in structure but it is really important.

Humans get much of their energy from starch, but can't digest cellulose at all.

You really should know that DNA is used to encode information in living things.

You probably know that it has a double helix structure

Each of the two chains is made up from a complicated polymer made up from four monomers.

We don't need to know the names of the monomers, though we should know that they are called Nucleotides.

But we do need to know that they can pair up - which is what links one helix to the next.