NIT

It is difficult to predict. Go for JEE Mains counselling or use shiksha's college predictor for references.

Check the website of NIT, Jalandhar. You can know about the cutoff for OBC category on the same.

It would be safe to assume that 140 marks would mean a rank around 35k-40k. I am taking the upper bound to ensure the worst case scenario. If you want to aim for computer science and engineering branch only, then there is a very slim chance that you would be able to get into any NIT directly. You would have to opt for internal shuffling which comes with the obvious risk of getting stuck with a branch that you don't want. If you decide on another branch that you would like to pursue, then maybe you can get an NIT.

The following NITs are ranked better than CUSAT: Trichy, Warangal, Calicut, Rourkela, Motilal Nehru National Institute of Technology (MNNIT), Durgapur, Jamshedpur, Kurukshetra, Jalandhar, Patna, Silchar and Hamirpur. It is obvious that CUSAT is not better than these NITs but it is not a bad choice if one can't get admission into any NITs.

To get admission in NITs and IITs, you need a strategy. You need to make your basics clear and rigid so that you can move forward. You can read NCERT books. You should practice as it will help you to understand the theories in a better way and also you will come across some unknown methods to solve a particular problem.
You can collect the previous year question papers with their solutions as it will help you to analyse the pattern. You should revise the areas in which you are strong, but work on the areas in which you are weak.
Best of luck.

BITS-Pilani, VIT University, Manipal University, Thapar University, SRM, BIT are recommended options. You may refer to following link for ranking of top engineering colleges in India: https://www.shiksha.com/top-engineering-colleges-in-india-rankingpage-44-2-0-0-0

You need to score around 150 marks to get admission in NITs.

If you belong to general category then you need to score more than 150 marks.

You need to qualify JEE Mains exam to get admission in NITs.

You need to qualify JEE Mains exam to get admission in NITs and JEE Advanced exam to get admission in IITs.
Kindly visit the link mentioned below to know about the colleges offering B.Tech in biotechnology:
https://www.shiksha.com/top-bio-technology-colleges-in-india-rankingpage-54-2-0-0-0