Dangers in running microsoft on the mac?

Hi - apologies for my ignorance here. I'm looking to get a mac (likely a macbook pro) but want to be able to run Office (as its used so much in what i do and what others do at University). I understand i can get thie through the Microsoft Academic download in the UK (which gives outlook also). However, one of the reasons for looking at the mac over the PC is the lack of viruses. If i run Office/Outlook does that expose me? If so do i then need AV and firewall after all? And is that specific to the Microsoft "part" of the mac. I appreciate i may be mixing concepts here but that's because i'm only used to using a PC and haven't had cause to consider this stuff until now. Thanks!