I am not a recent student but I have friends who are behind the camera. That you are: able to pay for it, an honest letter of purpose, that you are somewhat creatively talented, studious and determined, have relevant information in your recommendation letters, a portfolio that reflects your level of knowledge, skills and interest (come as you are, you don't need to be an expert but articulate) and a good academic transcript. For every school those qualities vary in level of importance.

A conformist.

Beginning art classes would be super helpful. I personally took a beginning drawing class and also a 3D design class. Both have been useful in my M.Arch. The skills you would learn in classes like that translate wonderfully to architecture. 

And my undergrad was in a foreign language, so don't worry about your biology! 

Definitely don't worry about having a background in biology.  Most schools like their MArch classes to be full of people with diverse backgrounds.  I would think you would want to use as a strength and point out what unique point of view/perspective you can provide with this background.  

Otherwise, take some drawing classes, painting, or computer classes in Adobe Photoshop, Illustrator, InDesign, etc., that would be helpful.  A lot of MArch programs that are geared for people with unrelated undergrad degrees include a summer session that will help you gain some skills prior to the first semester.

I think they just want to know you are truly interested in architecture, you understand what you're getting yourself into, you can pay for it, and are willing to do the work.  It is a ridiculous amount of work.  

I also have different background before going to March. What I include in my portfolio was some snapshot of candle cake melting for 3hours, exploded human body reconstruction, snapshot of biomass harvesting for one month....I think my school faculty are geeks.