In my school biochemistry classes are categorized as chemistry class, and they start with the code CH. I guess it's true for many other schools...
So it depends on how MY school classifies it, and not specific med school policy? That seems rather strange. It would be odd for X med school to count biochemistry for student A whose school puts it under upper division bio but not for student B whose school puts it under upper division chem.
OP, you should contact your school. Most schools have different requirements. You couldn't count it at mine, but that doesn't mean that you won't be able to at your institution. Go meet with an advisor.
No, the undergrad does not matter. The med schools are the ones that decide whether or not the courses count as prereqs.
For me, I don't see strong connection between genetics and biochem.I think it depends on the size of the school. The smaller the departments the more likely biochem is in the bio department, but at larger schools it will be apart of a separate, biochemistry department. Either way, I would highly recommend taking Genetics before Biochem, but would actually suggest taking both.
For me, I don't see strong connection between genetics and biochem.