Hi Anandhi

As per the difficulty level, it totally depends on you. The few popular colleges are

1.TIFR biological sciences department (offers integrated m.sc+PhD) .Admission is through TIFR JGEEBILS exam.

2. NCBS, Bangalore. same procedure and exam like TIFR

3.Hyderabad University. . Holds exam autonomously

4. JNU . New Delhi. admission through JNUEE

5.IIT Mumbai

6. Jamia Millia Islamia . Holds separate exam

7. Maharaja Sayajirao University Of Baroda. Holds exam at University campus separately for Biochemistry and Biotechnology

Hope this was helpful.