APOPTOSIS Flashcards
What is the ratio of cell death and renewal for a healthy cell?
rate of cell death=rate of cell renewal
Define apoptosis
is programmed cell death. it is a genetically controlled process that is a highly regulated form of self destruction
When may apoptosis occur?
- when cells are at the end of their natural life
- when he cell is dysfunctional or diseased
- there is an excessive number of cells
What is the unplanned form of cell death called?
-contents spill out causing inflammation
What are the main physical characteristics of apoptosis?
- cell shrinks
- plasma membrane forms blebs
- nucleus and cell organelles fragment
- cell breaks up and forms into parcels known as apostolic bodies which are engulfed by phagocytic cells
What are the two pathways of apostolic death?
- Intrinsic/mitochondrial pathway
- Extrinsic pathway/death receptor pathway
What is the role of the mitochondria in apoptosis?
mitochondria are vital in determining how and when damaged and stressed cells recognise its time to die
What occurs in the mitochondrial pathway ?
when activated pores form in the other membrane of the mitochondria in the damage cell. the pores release cytochrome c into the cytoplasm which intern aggregates with compounds to activate caspase 9 initiating the caspase cascade, dismantling cell and fragmenting DNA
What occurs in the extrinsic pathway?
the extrinsic pathway is activated when messages molecules form outside the cell bind to death receptors on plasma membrane signalling “it’s time to die”. The first step involves cleaving inactive pro-caspase to activate cascade 8 which initiates the caspase cascade
What is the role of caspase?
to demential the cell in an orderly manner, fragment DNA and package various components into apoptotic bodies
Do all cells contain molecules for its own self destruction?
yes
