• Cell undergoes programmed cell death where cell components are orderly disposed of
    • Cell shrinks and then lysosomes’ hydrolytic proteins (proteases, amylases [carbs], nucleases, etc.) fragment DNA and organelles that are packaged vesicles digested by white blood cells
  • Caspases: main proteases, enzymes that cut up proteins and carry out apoptosis.


  • Allow for the normal development and maintenance of an organism by selectively killing infected, damaged, or finished cells in an orderly way so dying cell doesn’t leak digestive enzymes
    • DNA damage (mutation) in nucleus
    • Release of extracellular death signal that binds to receptor and initiates phosphorylation cascade that activates nucleases (nucleic acids) and proteases (protein) that break down the cell
    • Protein misfolding in the nucleus (ex. alzheimers)
  • Mutations cause cancer, so apoptosis helps prevent this


  • Ced-9 prevents apoptosis by inhibiting caspases