in short and simple way is “programmed cell death”. This occurs in multi cellular organisms. This happens due to certain biochemical events which causes characteristic changes in cell (morphology) and even their death. These changes are:
- Nuclear fragmentation
- Cell shrinkage
- Chromatin condensation
- Chromosomal DNA fragmentation
What is the Difference Between Necrosis and Apoptosis?
Necrosis is a type or form of traumatic cell death which is caused due to acute or chronic cellular injury. In contrast, apoptosis is referred to the death of cell by natural in built cell mechanisms which is called as programmed cell death.
Process of Apoptosis:
The mechanism of this is controlled by different types of cell signals which can be originated extracellular or intracellular.
Extracellular signals include:
- Growth factors
- Nitric oxide
These signals cross the plasma membrane of the cell and transducer the response. These signals may be positive (to trigger) or negative(to repress) affect of apoptosis.
Another extrinsic pathway for initiation of PCD is identified as high level of calcium concentration inside the cell induced by drug treatments which can cause apoptosis through a protease(which binds the calcium) known as calpain
Intracellular signals are initiated by cells due to stress which causes cell suicide. Nuclear receptors of cell bind with:
- Nutrient deprivation
- Viral infections
- Increased level of intracellular calcium concentration.
Cellular component like poly ADP ribose polymerase also supports the process of apoptosis.
Apoptotic signal causes the regulatory protein to initiate the Program Cell Death pathway before the actual cell death is precipitated by enzymes. This lead the apoptotic signals for cell death or make the process be stopped if the cell no longer needs to die. Various proteins are needed for this process but, the two main processes of regulations identified are:
- Targeting of mitochondria functionally
- Directly transferring the signal through the adaptor proteins to the apoptotic mechanism.
This is one of the best research topic among the scientic field revolving around, mostly for using this mechanism for the cure of cancer “the deadly incurable disease”.