Genome 9th Entry: Death

Ridley explores cell death and cancer.  He introduces the idea that cells reproduce themselves when they are not supposed to.  On chromosome 17, a gene called TP53 is responsible for suppressing cancer cells, also called a tumor-suppressor gene.  In contrast, the oncogenes encourage cell growth.  Oncogenes can cause cancer when they are switched on and tumor-suppressor genes cause cancer when they are switched off.  Ridley explains that various types of cancers may be caused by mutations of the TP53.  In cancerous cells, the protein for TP53, p53 stop working properly, and stop signalling apoptosis or programmed cell death.