Final answer:
An oncogene is a gene that becomes overactive due to a mutation, contributing to uncontrolled cell growth.
Step-by-step explanation:
An oncogene is a gene that becomes overactive due to a mutation, contributing to uncontrolled cell growth. Oncogenes are mutated versions of proto-oncogenes, which are normally quiescent counterparts. When proto-oncogenes are mutated, they can modify their expression and function, resulting in increased activity or production of the protein they encode. This alteration in the proto-oncogene turns it into an oncogene, which disrupts the normal regulation of the cell cycle, leading to uncontrolled growth.
For example, the oncogene myc is aberrantly activated in Burkett's Lymphoma, a cancer of the lymph system. Overexpression of myc transforms normal B cells into cancerous cells that continue to grow uncontrollably, resulting in the formation of tumors. These tumors can interfere with normal bodily functions, such as eating.