To be eligible to take admission in integrated PhD Biology in IISER after B.Sc general following conditions are to be fulfilled:

1.In the JGEEBILS 2019, you need qualifying marks in the exam AND 

2.60%(general/OBC)and 55%(SC/ST) cgpa in your Bachelor degree . Both of them is required. 

You can also appear for this exam in last year of your bachelor's degree. I hope it helped