Indian Institute of Science

No, IISc only offers management degree, i.e. MBA.

To know the number of streams at IISC Bangalore, check out the course list below:
https://www.shiksha.com/university/indian-institute-of-science-Bangalore-22350/courses.

Hello Sameeksha,
GATE is the exam to be given for seeking admission for different ME courses in IISc. Of course with obtaining the tag of "institute of eminence" fron GoI recently, the research as well as PG courses may undergo a revamp in times to come.

Hello Kuldeep,
IISc admits close to 400 students across different programs of PG. Basic eligibility is graduation in engineering and clearing of GATE paper. I am attaching a link that will give you all the required information.
https://www.iisc.ac.in/admissions/m-tech-m-des/

IISc offer M.Sc in biology. You can visit website of IISc for more details.
Website: www.iisc.ac.in

It is a 4-year course.

Yes, the admissions were over in April itself.

Hello Jyoti,
It's very tough to say which department of IISc is better than the other. In fact each department competes with another for academic excellence in this institute. I would rather advise you to select the topic that fascinates you the most amongst a variety of subjects that you are eligible. I am attaching a link for you:
https://www.iisc.ac.in/admissions/research-programmes/

The best colleges are
-Indian Institute of Space Physics (Kolkata)
-Raman Research Institute (Bangalore)
-IUCAA (Pune)
Good luck.