Should we talk about the three major causes of cancer: oncogenes, oncoviruses, failure of tumor repression genes? Oncogenes typically fall into three categories of proteins involved in cell signaling: growth factors, tyrosine kinases, and transcription factors. For example, the proto-oncogene ras is a signal transducer, normally inactivated by extracellular signals. The smart child will learn about the chemical cycle starting with growth factor, receptor tyrosine-kinase, membrane-associated G-protein, serine/threonine kinases, transcription factors, and finally the CDK/cyclin/E2F which trigger passage through the restriction point. We would also cover chronic myelogenous leukimia, in which the leukemic cells have a reciprocal translocation between chromosomes 9 and 22. In addition, we will go over the p53 tumor supressor gene, coding for a transcription factor, its failure to trigger apoptosis. The final examination at the end of the game will also cover the difference between intercalating agents such as acrydine orange and alkylative agents such as nitroguanidine. For extra credit, the gifted child will draw diagrams showing the difference between a vertical cut and horizontal cut in the Holliday model, and how this affects heterozygotic crossover supression.