Yes they do! You have to have a good LOR to be competitive and eligible for interviews. As for persons i would go for whoever knows you the best and can evaluate and gauge your work ethics. So that can be profs, supervisors, employers, etc. But NOT family members or neighbours.
LORs are very important in the application process. I got one from biology professor and 2 pharmacists. Basically a science teacher, a pharmacist, and an employer will do.