The following list will give an idea about the important units as they will give you a better situation representation.

Diversity in living world - Least important , 3 to 4 Questions maximum

Anatomy and Morphology of plants - You can ignore Morphology to some extent but Anatomy will definitely grant you some good'ol easy marks , 4 questions

Cockroach - 2 Questions from a single chapter , it's an easy scorer(Read NCERT thoroughly for this chapter especially)

Cell structure , cell cycle and biomolecules - forms nearly 5 to 6 questions

Plant physiology - super scorer unit , very important , nearly 10 to 12 questions are usually expected

Human physiology - another super scorer unit , again very important , nearly 12 to 15 questions usually expected

Reproduction - important and should be on your tips , can easily fetch you a good 7 to 8 questions

Genetics and evolution - prep this up real good for this is the unit with a good number of questions and is the most tricky one , 10 to 12 questions

Human health , Crop improvement and Biotech - expect 10 questions from this unit

Ecology - most important unit of all , easy to learn , very high scoring , 15 questions expected

All the best for your preparation.

Plant diversity and animal diversity, morphology and anatomy ,genetics,GE and it's application human and plant physiology.