Final answer:
The mitotic index changes over time vary based on the type of mutation in the p53 gene. Cells with dysfunctional or mutated p53 genes have an increased mitotic index, leading to unchecked cell growth and potential tumor development.
Step-by-step explanation:
The mitotic index refers to the proportion of cells in a given population that are undergoing mitosis. When considering cells with mutations in the p53 gene, we need to account for the role of p53 in cell cycle regulation. The p53 protein acts as a tumor suppressor, which helps in the prevention of cancer by repairing DNA or by initiating cell death when the DNA cannot be repaired. If the p53 gene is mutated, the regulation can be compromised, leading to unchecked cell growth and division.
Cells with two mutations or cells lacking a functional p53 gene fail to effectively halt the cell cycle for DNA repair or initiate apoptosis, leading to an increased mitotic index. This heightened state of cell division propagates the mutation and allows for the accumulation of further mutations, thus contributing to tumor growth. Conversely, cells with a fully functional p53 gene are likely to have a regulated mitotic index as the p53 ensures proper DNA damage responses are carried out. Therefore, the mitotic index varies based on the type of mutation in the p53 gene and the number of mutations present.
The correct answer to the question 'How does the mitotic index change over time for cells with one, two, or no mutations in the p53 gene?' would be C. It varies based on the type of mutation.