Assuming you are from Biology-physics-chemistry stream.The path you choose will depend on the research area you want to focus. 

The following are the different options:

-You can do simply B.Sc. in Biology and further M.Sc. from a reputed institution for 
career as a scientist. After M.Sc. you will be required to do Ph.D. 
According to your interest you can choose Botany or Zoology. 

-You can take admission in B.Pharm. and further M.Pharm. for research works 
related to pharmaceuticals. 

-You can go for MBBS and then further higher studies oriented to research work.

You will have to get in research field and then your research and project works will 
decide when you will become a scientist.