Programmed cell death

Definition

Programmed cell death, also known as apoptosis, is a regulated process that leads to the orderly and efficient elimination of damaged or unnecessary cells. It plays a crucial role in maintaining cellular homeostasis and immune system function.

5 Must Know Facts For Your Next Test

1. Programmed cell death is essential for the removal of infected or cancerous cells by T lymphocytes.
2. Caspases are a family of enzymes that execute the apoptotic process by cleaving specific proteins within the cell.
3. Failure in programmed cell death can lead to autoimmune diseases or uncontrolled cell proliferation, such as cancer.
4. During programmed cell death, phosphatidylserine flips from the inner to the outer leaflet of the plasma membrane, signaling phagocytes to engulf and remove the dying cell.
5. T lymphocytes can induce apoptosis in target cells through Fas-Fas ligand interactions or release of cytotoxic granules containing perforin and granzymes.

Review Questions

• What role do caspases play in programmed cell death?
• How does failure in programmed cell death contribute to disease?
• What mechanisms do T lymphocytes use to induce apoptosis in target cells?

Related terms

Apoptosis:

A form of programmed cell death involving regulated cellular processes.

Caspases: A family of protease enzymes that play essential roles in apoptosis.

Fas Ligand (FasL): A protein expressed on T lymphocytes that binds to Fas receptors on target cells to trigger apoptosis.