Hello Shefali,

The subjects and their weightage are given below -

Engineering Mathematics - 15%

General Aptitude - 15%

Subject Questions - 70%

and the best books you can consider according to the part of the subject are-

Linear Algebra -  Advanced Engineering Mathematics by Erwin Kreyszig

Calculus - Intermediate Mathematics by B.V.Sastry and K.Venkateswarlu

PROBABILITY AND STATISTICS - Introductory methods of numerical analysis by SS SASTRY.

NUMERICAL METHODS - Higher Engineering Mathematics By B.S Grewal

MICROBIOLOGY - Microboiology by Lansing M. prescott

BIOCHEMISTRY - Biochemistry by Lehninger

MOLECULAR BIOLOGY AND GENETICS - Principles Of Genetics 8th Edition by Eldon John Gardner, Michael J. Simmons, Peter Snustad

PROCESS BIOTECHNOLOGY - Process Biotechnology Fundamentals by S. N Mukhopadhyay

BIOPROCESS ENGINEERING - Bioprocess Engineering Principles by Pauline M. Doran 

PLANT AND ANIMAL BIOTECHNOLOGY - Carl Pinkert Transgenic Animal Technology: A Laboratory Handbook. Chawla HS, Plant Biotechnology: A Practical Approach

CHARACTERISTICS OF ANIMAL CELLS - Cell Biology: De Roberties.

IMMUNOLOGY - Immunology By Kuby.

RECOMBINANT DNA TECHNOLOGY - Gene cloning and DNA analysis by T.A.Brown

BIOINFORMATICS - Introduction to Bioinformatics 3rd edition by Arthur M. Lesk

All The Best.