Steroids

The example here shown is cholesterol

its parts in this way:

• the cyclopentane- perhydrophenanthrene ring system, with its 2 mehyl groups
• the side chain, with its 3 methyl groups
• the C=C double bond
• the alcohol group (OH) in position 3, which is the polar part of the molecule

It is interesting to the hydrophobic part from the hydrophilic part (this defines the lipid position within biological membranes).