For chemistry portion heterocyclic compounds is a very important topic or not?? i am asking because i am struggling with this!

for chemistry portion,is heterocyclic compounds a very important topic or not?? i am asking because i am struggling with this! particularly for iit jam BT please guide me which are the most important topics for organic chemistry and the chapters of organic chemistry of 11th and 12th are sufficient??? Or it requires high level preparation so plz guide how should I prepare.