hey, you must have to take entrance classes because they will guyid you more in the correct path. good luck ans wishes for you final year and your masters. 

have a great future ahead.

You have to appear in GATE , and for that either ubcan join a coaching or u can self study

Mtech In Biotechnological engineering shall require GATE exams for all IIts and NIT.
Some top preparation tips shared below for GATE preparation.

https://engineering.careers360.com/articles/gate-preparation-tips-from-toppers-and-experts

To know more about Scope and opportunities for Masters in Biotechnology check below.

https://www.careers360.com/news/3181-Biotechnology-What-to-study-where-to-work