Final answer:
Normal cellular genes that regulate cell growth and division are known as proto-oncogenes, which can become oncogenes when mutated. Proto-oncogenes code for proteins that promote normal cell cycle progression, while tumor suppressor genes prevent uncontrolled cell growth.
Step-by-step explanation:
The normal cellular genes responsible for cell growth and division are called proto-oncogenes. These are genes that code for proteins which positively regulate the cell cycle, contributing to normal growth and proliferation. However, when these proto-oncogenes are mutated, they can become oncogenes, which are capable of causing normal cells to become cancerous. These alterations can lead to inappropriate or unregulated cell division, characteristic of cancer. An important aspect of proto-oncogenes is their role in coding for proteins that are required for the normal progression of the cell cycle, such as cyclins, growth factors, or cell-signaling molecules.
In contrast, tumor suppressor genes work to inhibit cell division and promote apoptosis when cells are damaged. Well-known tumor suppressor genes include p53, which also functions as a transcription factor. Both proto-oncogenes and tumor suppressor genes are crucial in maintaining cellular balance and preventing the development of cancer. A series of mutations within these genes can transform a normal cell into a cancerous one, with oncogenes promoting uncontrolled growth and tumor suppressor genes losing their ability to regulate and inhibit this growth.