Much prep work goes on the days before our group meets, because each child chooses something from the chapter to report on. Toddzilla wanted to work on the endoplasmic reticulum because our book described it as the garbage/delivery man of the cell. We made a garbage truck out of cardboard; then he put his facts inside on crumbled pieces of paper.
Elbow chose Galen, a Roman doctor who treated the gladiators. Bobo worked on DNA and the Human Genome Project.
We're very fortunate to have quite a few parents in the group who are doctors or scientists. The children got a chance to see their own blood cells (if they wanted to be pricked!) under the microscope.
We also added organelles (candy) to our cytoplasm (jello) to review all the parts of the cell.