I am half-way through the excellent Crash Course Biology from Godfathers of YouTube Hank and John Green. It is entertaining, well-informed and snappily presented in twelve-minute chunks. At forty episodes that's still nearly eight hours of watching but I recommend it for our PAL and TAL as it is exactly at A-level. For International GCSE it may be a bit much, but some of the inheritance videos are bang on. Enjoy!
