no .. its not compulsory. You can choose other streams too. For better opportunities, you can do MBA. Some prominent schools that you can consider except IIMs are

Shailesh J. Mehta School
Xavier's Labour Relations Institute, Jamshedpur
Mittal School Of Business, Lovely Professional University, Punjab
Department of Management Studies, IIT Delhi
Indian Institute of Foreign Trade, Delhi 
Management Development Institute (MDI), Gurgaon
Bharathidasan Institute of Management (BIM), Trichy
Narsee Monjee Institute of Management Studies, Mumbai
National Institute of Industrial Engineering (NITIE), Mumbai
SP Jain Institute of Management, Mumbai.

Hello Himani,

You ofcourse are eligible for jobs after a B. Sc degree in Biotech. 

Following are some jobs:

Civil service after taking the UPSC.

Content writing on BioTech.

Face to Face Fundraising in Humanitarian organisations.

You can also do your higher studies in other streams like:

An MBA

Master's in Liberal Arts/ Journalism

A B.Ed (bachelor of education)