SKYLER K., SCOTT D., and GEORGE M. get a close look at a little mitosis action in onion root tip cells. We used root tips because the cells are rapidly multiplying to increase the surface area for water absorbtion. Remember that we have a test Wednesday on Diffusion, Photosynthesis, Respiration, and Cell Reproduction. Make sure you organize your notes and handouts because you will get to use them on the exam. NOT your books, however.