http://youtu.be/BmFEoCFDi-w View full lesson: http://ed.ted.com/lessons/how-do-cancer-cells-behave-differently-from-healthy-ones-george-zaidan How do cancer cells grow? How does chemotherapy fight cancer (and cause negative side effects)? The answers lie in cell division. George Zaidan explains how rapid cell division is cancer's "strength" -- and also its weakness. Lesson by George Zaidan, animation by TED-Ed.