If I have not taken computer Sci. In 11th and 12th can I do computer science engineering? Is it possible.and also I am a biology student.
To do engineering, you need to have pcm in your class 12th board exams which is not true in your case.But i would suggest you to do BCA(Bachelors of Computer Application) in any good college if you want to study about computer and programming.
Good luck.

CS in engineering has nothing to do with ur taking up computer science in 11th and 12th .
But if u want to take up CS just try to learn computer languages before entering college just to keep things east for urself .