Colleges in Kolkata

Hello Soumya,
You may refer the link below for the list of colleges that offer media science courses in Kolkata:
https://www.shiksha.com/mass-communication-media/colleges/colleges-kolkata

Heritage institute of technology if one of the best private Colleges of West Bengal. Placement is very good there but just for CS/IT branch.Other branches has average placement.

M.Com will lead you for further higher studies as well as jobs where as B.Ed will only provide you a high school job.

Although it cant be predicted with a certainity, but if you are a boy, you can expect to get through if you have above 93.5%. Girls might need little more than 94.5%. This is because morning batch which is boys only has a little lower cut off due to more seats. Girls can get into evening batch which is co-ed.
Its a great college for B. Com Honours, if you are considering it as an option.

Yes, for biotechnology you need to have a background in physics, chemistry and biology.
You seem to have studied these subjects so you are eligible to pursue biotechnology.