This lab uses pieces either from a kit (obtained from Biological Supply houses) or pieces can be made by students using paper or felt. I have submitted other labs using these same pieces for DNA structure and replication, so if you use these labs, you can save the pieces. This particular lab just needs one more sheet, sheet "C" if you have made the others. My students do really well with these labs and I have used them for years! Hope it helps you explain and assess these concepts.