AIIMS

Hi. For information, you can see the below link
https://www.shiksha.com/college/aims-Jodhpur-all-india-institute-of-medical-sciences-64869/course-m-sc-in-biochemistry-380161
Thanks.

As per the AIIMS Prospectus, there is no AIIMS available in Pune. So please SEE the AIIMS Prospectus for more clarity. However AIIMS Delhi is the best.

You have to appear in AIIMS B.Sc. Courses Entrance Examination. The eligibility criteria is given below. Eligibility : Candidates who have Passed the 12th Class under the 10+2 scheme/Senior School Certificate
Examination or Intermediate Science or an equivalent examination from a recognised University/Board of any Indian State with English, Physics, Chemistry and Biology and has a minimum aggregate marks required in qualifying examination I. e.10+2 or equivalent is 55% for Gen/EWS/OBC and 50% in case of SCs/STs categories.

Yes, you can get admission. Depending on your score.

AIIMS only provide M. Biotech in the stream of biotechnology which is a master's degree. The college which provides B.Tech Biotech like IITs, NITs, CFTIs and GFTIs etc. You have to gone through JEE-Mains then JEE Advanced. The 12th subjects combination for JEE Main for Biotechnology is given below. Subjects: Candidates must have to take minimum 5 subjects in 12th/equivalent examination. Candidates appearing for JEE Main must have passed class 12th with Physics & Mathematics as compulsory subjects along with anyone from the Chemistry/Biotechnology/Biology/ Technical Vocational subject.

No, you can not. The subjects changes are not allowed in class 12th. However, changes can be made before joining the class 11th.