Final answer:
Apoptotic bodies display phosphatidylserine on the outer membrane, signaling for their removal by immune cells, which is crucial for preventing autoimmunity and for development processes.
Step-by-step explanation:
Apoptotic bodies express phosphatidylserine on the outer layer of the cell membrane. During the process of programmed cell death, which is known as apoptosis, phosphatidylserine, which is normally found on the inner leaflet of the plasma membrane, flips to the outer leaflet.
This externalization serves as a signal for macrophages and other cells that can engulf these apoptotic bodies, leading to their clearance from the body. This process is an integral part of the immune system's regulation, preventing the potential development of autoimmune diseases by removing cells that mistakenly target self-proteins.
It is also a key factor in normal development, such as the separation of fingers and toes during embryogenesis, as well as in the removal of cells that are damaged beyond repair.