Hello
Scoring good marks in biology alone cannot provide you a MBBS seat as the competition level is very high and you need to have a better score to secure a seat in govt medical college. You need to atleast have a score of 500+ to be on the safer side of securing a seat in general. The cutoff varies every year depending upon your state and the competition level.
However with a relatively lower score you can get a private or deemed college

Goodluck I hope this helps you