There is becoming a perception by both adcoms and applicants that since the MCAT has Biochem as a core competency, that most students should have a Biochem course. So you are likely to get into the "defacto" competitive requirement where a large portion of applicants will have it. Thus, while not a formal requirement, it may have a minor impact just against the pool of those who do.
Having said all that, if you have a strong application with just the required courses, then go with it.