Hey Sumana

Well every institute conducting entrances has there own preference to what topics are important for the exam and so is there for biological sciences as well.Few of the most important topics which are covered by almost all the entrances are as

Biochemistry: enzyme kinetics, metabolic reactions, cycle

Microbiology: read prescott thoroughly

Molecular biology: entire Watson and Crick

Immunology:read the summary points in each chapter of kuby

Chemistry: atleast plus 2 level

Genetics: Russell thorough read

Cell biology: Lodish