My humble opinion? I would not worry about retaking Cell if you got what knowledge you needed out of the class. Yes, you will probably actually use some of the molecular stuff at a later date, but not to the full extent they taught you in the class. Cell is a bit over the top for our uses, at least here at Colo State. Here at least, it is taught from a molecular perspective, and unless you are planning to go into say a PhD in neuroreceptors, taste cell transduction or whatever, you probably already know all you will ever need on the subject. So simply move on, and ace the rest of your classes. This coming from someone who did repeat/delete Cell, and also has just finished a year of grad level molecular phys. Adcoms know there will always be those white elephant classes that an otherwise excellent candidate simply trips on. As long as they are the exception rather than the rule, you are better off moving on, and killing the follow-up classes instead. That will prove your academic merit far better than staying in the same rut and redoing past mistakes. That is what I have been told. A&P is far more important for our purposes.