What is the final action taken by caspase enzymes during apoptosis?

Caspase enzymes play a crucial role in the execution phase of apoptosis, which is a programmed and regulated process of cell death. The final action taken by caspases is the fragmentation of DNA. This process involves caspase activation leading to the cleavage of several key cellular proteins and structural components, ultimately facilitating the systematic dismantling of the cell.

During apoptosis, endonucleases are activated, which results in the cleavage of genomic DNA into smaller fragments, commonly seen in a "laddering" pattern on an agarose gel. This DNA fragmentation is important as it ensures that the dying cell does not remain intact, thus minimizing inflammation and damage to surrounding tissues. It is a hallmark feature of apoptosis and indicates that the cell is irreversibly committed to dying, leading to eventual clearance by phagocytes without releasing harmful cellular contents.

The other choices do not represent the final action of caspases in the process of apoptosis. For instance, cell cycle arrest is typically a response to stress or damage, not a direct action taken by caspases. Cell lysis is associated with necrosis rather than apoptosis, and repair of cellular damage is contrary to the intent of apoptosis, which is to eliminate damaged or unwanted cells rather than repair