Define the Structure of Vitamins?

For your convenience, however, we have given the structures of these vitamins here in the text. Look at Figure which illustrates the fat-soluble vitamins. As you go through these structures, you would have noticed that all these fat-soluble vitamins have certain common features such as an aromatic ring structure with an aliphatic side chain, one or more double bonds either in the ling or in the side chain and a functional group such as an aldehyde (CHO: in vitamin A), ketones (C = 0: in vitamin K), methyl (CH₃) or hydroxyl groups (OH: in vitamin D)