Well, brother I would first apprecate to your decision of prefering your interest than going with herd race. 

So, regarding to your question. At IIT, for Bio-Tech, a normal PCM candidate can take the course provided his rank is good enough to get that course. Their is no such need of studying indepth biology nor it has much

Also, let me tell you Bio-Tech involves natural applied physics, biomolecules, protien study, mendalive's study etc. 

Hello dear, for getting any stream in IIT you have to qualify JEE Advance and for that, you have to master  PCM and  PCMB is not an option in JEE.

Hello Shreyas

If you gave JEE mains then you must be having Maths and so, you can see that you must have mathematics in order to pursue an engineering degree in IIT. Hence, along with that in order to have a basic understanding of Biology, you must have had either Biology or Biotechnology also as your subject. Then, only you are eligible to give JEE. Giving JEE means you must have mathematics.

So, Maths will be included.

Hello Shreyas Kulkarni!

Basically you can take any of the one i.e either PCM ( Physics, Chemistry & Maths ) or PCB ( Physics, Chemistry & Biology ) because only for doing MBBS/BDS it is compulsory to take PCB and for any other course you can take either PCM or PCB....

-> But the preferred for you to take is PCB which Physics, Chemistry & Biology because it will be more related to BioTechnology as you have set the goal for BioTechnology in B.Tech...

-> I really want to appreciate you interest in Biotechnology before going into your higher secondary studies... keep it up.. just work hard in your school studies and try to give IIT JEE and AIEEE and get seat in some reputed universities and do B.Tech BioTechnology and work hard in it...

-> Biotechnology is one of fast emerging field now a days and there are lot of projects currently going on which is based on Biotechnology...

-> Just put your best and work hard then for sure you will have a bright future...