You don't really need to know chemistry in terms of organic chemistry from what USF med students tell me.
However, you need to understand biochemistry and its clinical aspects from what I have heard and seen of the medical school text book which sits in my research professor's office at USF COM.
You do need to understand bio, because that is the basis of everything in medicine.
I mean no offense, but that is kind of obvious that you need to know biology to treat humans whom are biological organisms too. No you don't need to know ecology to be good in medical school, but of course you need to know your Anatomy/Physiology and things like Genetics and Cell and Molecular Biology. Now do you need to take every single one of these courses at the undergrad level???????
No you don't need to take them all at the undergrad level. However, it will help a little bit later on, when you do have take them. Also, it may show that you are capable of handling sciences if you take them at undergrad level.
In regards to Pharmacology, Pharmacology has a lot of biochemistry basis, so it is biological and chemistry as well, but with clinical aspects.