Your question is very good. There is usually one full question or the majority of one full question on genes, inheritance and reproduction in the section C of the LC Biology Paper. Also you may be asked on these in section A and on the experiments for section B.
So my answer to you is that you should not leave out anything if you are definitely planning on doing this question in the exam. What you should prioritise is the definitions, stages of gene reproduction and completing genotype calculations.
Also practice until you cant get it wrong by doing an a lot of previous exam paper questions :)