What are the two main mechanisms of cell death?

The two main mechanisms of cell death are apoptosis and necrosis. Apoptosis is a programmed and controlled process of cell death that occurs as a normal part of growth and development, allowing for the removal of unwanted or damaged cells without causing inflammation or harm to surrounding tissues. This process is vital for maintaining cellular homeostasis and is characterized by specific morphological features such as cell shrinkage, chromatin condensation, and DNA fragmentation.

On the other hand, necrosis refers to an uncontrolled form of cell death that usually results from acute cellular injury or lack of blood supply (ischemia). Necrotic cells undergo swelling, rupture, and release their contents into the surrounding tissue, which can lead to inflammation and further tissue damage. This process is often associated with pathological conditions and can elicit a significant inflammatory response.

The other mechanisms listed in the choices do not align with the primary natural processes acknowledged in cell biology. Metabolism refers to the biochemical reactions occurring within cells, mitosis is the process of cell division, and inflammation is an immune response that often follows cell injury, but they do not represent distinct mechanisms for cell death. Thus, apoptosis and necrosis are the appropriate terms for the mechanisms of cell death in this context.