Hello!

Before applying for the jnuee life science you have to complete your graduation with biology, for preparing life science you have to clear your basics of your graduation,before start preparing at first look at the syllabus of the entrance exam,,and then pic up the book of your graduation and start preparing those topics which is in syllabus, you can buy some help books,and you can also buy solved question papers of life science,, it will helpful for the preparation,

I'll tell you the important books that you should definitely refer for JNU or in case any life sciences exam

Cell biology-Lodish

Biochemistry- Lehninger

Stryer and Harper are quite good too

Molecular biology- Bruce Alberts

Microbiology - Prescott

Immunology - Kuby

Genetics- Gardner

Developmental biology- Gilbert

Biotechnology- Glick

Plant and animal physiology, evolution and ecology - 11th and 12th ncert books are enough

Thankyou!

Hope it helps!