Final answer:
In the absence of ATM, cells with DNA damage in G1 can incorrectly proceed to S phase, leading to mutations and an increased cancer rate. Cell cycle checkpoints like the G1 checkpoint and proteins like p53 are crucial for preventing this by halting the cycle for repair, with the correct answer being B.
Step-by-step explanation:
In the absence of ATM, cells that suffer DNA damage during G1 fail to arrest in G1 and enter the S phase before repairing the damage. Replication of damaged DNA leads to mutations, which contribute to the tissue damage and increase the cancer rate. The correct answer is B) DNA damage; S; mutations; increase.
Cell cycle checkpoints, such as the G1 checkpoint, ensure that cells do not progress through the cell cycle when DNA is damaged. Proteins like p53 play a crucial role in arresting the cell cycle until damage is repaired. If the damage is beyond repair, the cell undergoes apoptosis to prevent the propagation of the damaged DNA. ATM protein is involved in recognizing DNA damage and initiating the repair process. When absent, the cell cycle can proceed without the damage being fixed, leading to an increase in mutations.
Mitigation strategies for such situations include the presence of robust DNA repair mechanisms and apoptosis, which are essential for maintaining genomic integrity and preventing cancer development. In summary, cell cycle checkpoints and DNA repair are vital for preventing cancer, and the absence of functional ATM significantly disrupts these processes.