Organic Chemistry is something that one cannot neglect.
Basically, there is a fair bit of information that you have to
memorise like for exmaple, the different homologous series
(alkenes, alkanes, alcohols, carboxylic acids) and their
formulas. You will also have to give a definition on
isomerism.
You can check more info on your textbook under learning objectives
usually on the first few pages. You will also have to
memorise the different reactions to convert one substance to
another. (alkanes to alkenes or alkenes to alkanes)
You will need to know how to draw the structural formula of
the different compounds. plus a bit on macromolecules like
the difference between addition polymerisation and condension
polymerisation.