Hello aspirant,
I am here for helping you.
as per your doubt I am providing you a list of some Central entrance exams for biotechnology.

• AIIMS Biotechnology Entrance Test

• JNU (Jawaharlal Nehru University) Combined Biotechnology Entrance Examination

• CBEEE (Combined Biotechnology Entrance Examination)

• DU (University of Delhi) Biotechnology Entrance Examination.

if talking about how much marks you need to score for having a government college so you should be in safer side so for having a government college you need to score at least 70% of the total marks, for having a good college you need to score more than 50% marks out of your total marks.
I hope it will be beneficial for you.
Feel free to ask any query in comment section.
Best of luck.