This is great for IGCSE or IB to outline the basics of enzyme action. It is not detailed, but gives a good visual overview of anabolism, catabolism, specificity, effect of temperature, etc - all in a continuous animation.
Animation of pollination, fertilisation and seed formation - good for IBH but also a useful link for IGCSE (even though it is not on the syllabus, it links pollination and seeds!)
A really lovely stop motion animation showing normal meoisis and non-disjunction meiosis resulting in trisomy 21 - using smarties and coloured liquorice canes!
Animation and tutorial showing the experiments that led to the understanding of how certain plants detect light and so control the flowering. Includes descriptions of phytochrome, Pr and Pfr.