I read lots of papers on longevity and nootropics. I haven't really done biology research since I'm an astrophysics major who does astro research. However, I know that bioinformatics+systems biology+biophysics departments do *really* value people with quantitative backgrounds like mine, so I'm quite interested in those programs.
And of course, I have to show that I have interest and experience in biology. The only way I can really do this is by showing that I've read papers (although I did get a 3.7 in a grad-lvl biophysics of neurons course). I didn't have the time to go through introductory biology since I had so many other quantitative courses that I wanted to take, and this prevented me from being able to take most upper-level biology courses (but I have self-studied significant amounts of biology)