How helpful are grad level classes for improving apps?

[vnatch]

I will be applying to PhD programs in molecular/cell biology programs this cycle, and I have heard that it looks good if grad schools see that I have taken a grad level class. Does anyone have any more information about how much this actually helps or hurts people during the application decision? Additionally, I would assume that taking a grad class is only helpful for the application if it is in a field related to biology. Would schools not care if I have graduate credit in a different subject? Finally, even if I take a grad level class this fall, will schools get to see this? They will see it on my transcript when I apply but the grade won't be in until after the deadline has passed, so I'm not sure if the schools would even get to see it.

I am asking because I am currently deciding between a few options for my schedule this semester. Basically, I am already done with the bio major so I don't technically need any more classes in it. Additionally, I have a second major in statistics that I still have classes for. I also want to devote as much time as possible to the lab I am a part of. So my three options are to (1) take one less class and devote the extra time to my research, (2) take a graduate level class in statistics (which would count toward my major), or (3) take a grad level bio class. The major con against the bio alternative is that none of the classes offered are really related to cell bio, most are evo/eco or behavior type classes.

I should say, that no matter which of those three options I choose, I will be taking a 2 credit Distinguished Majors Program seminar and 2 credits of independent research (in the lab I mentioned before). I'm not sure if grad schools all know exactly what this program is, but basically it's a research-driven honors program in the bio department. If anyone can give me some advice on this, that would be great!

[Bioenchilada]

Most schools will not really care about your senior year grades since they review apps before even the fall grades are available. Take the classes that you think will make you grow the most personally and/or academically.