Final answer:
Tumor suppressor genes require mutations in both alleles to lose their tumor-suppressing function, acting as a genetic brake to prevent uncontrolled cell growth.
Step-by-step explanation:
Tumor suppressor genes are crucial in preventing the uncontrolled growth of cells that can lead to tumor formation. For tumor suppressor genes to lose their tumor-suppressing function, both alleles need to be mutated. This is in contrast to oncogenes, where the mutation of a single allele can lead to cancer. Tumor suppressor genes act as a type of genetic 'brake' to control cell division, and when both copies of the gene are mutated or inactivated, this brake is released, potentially leading to cancerous growth. An example of a tumor suppressor gene is the TP53 gene, which produces a protein that regulates cell division and prevents the formation of tumors.
Tumor suppressor genes require both alleles to be mutated in order to lose their tumor-suppressing function. These genes normally regulate cell division and prevent the formation of tumors. However, when both alleles are mutated, the gene's function is impaired, allowing uncontrolled cell growth and the development of tumors.