As a science or pre-med student, you normally have to take biology and chemistry courses. The recommended order of the courses varies a bit by institution. On its website, Columbia University says that you should typically take basic chemistry courses before biology because chemistry is commonly used in biology. Thus, you need chemistry knowledge to do well.
Program Layouts
Organic chemistry is considered a higher-level course than introductory biology. Georgetown College recommends basic biology and basic chemistry in the fall of your first year for a pre-med track, and organic chemistry in the fall of your second year. Rutgers University advocates that same course order in its biological sciences programs. Thus, you should normally take some biology before organic chemistry.