I've been studying cell biology on my spare time. I've been using The Molecular Biology of the Cell (http://www.amazon.com/Molecular-Biology-Cell-Bruce-Alberts/d...) that in my opinion is a great book, and as far as I know, is well-respected in general.
Still, watching Sal's biology videos has been of great help. Although I think e.g. his organic chemistry videos are better executed (~10 minutes per video, a bit less packed, better splits by content), I still think that his biology videos are a super-valuable resource. I've been watching some MIT lectures too, but visualizations, which are necessary for biology, aren't properly visible in them. Of the free biology content in the web, Sal's videos are the best IMO.
Molecular Biology of the Cell
The description of the DNA --> RNA --> protein pipeline was really satisfying to someone with my background, full of codes, error-correction algorithms, and rate-limiting steps. I think of it as the Numerical Recipes of biology.
Get dozens of book recommendations delivered straight to your inbox every Thursday.