Cell death can occur either by necrosis or by apoptosis. Apoptosis is governed by precise molecular controls.
learning outcomes
You should be able to:
Compare and contrast necrosis and apoptosis.
Justify the role of apoptosis in an organism’s survival.
Describe how apoptosis is regulated.
What types of events initiate necrosis, and how do these events differ from those that initiate apoptosis?
Signals for necrosis include great damage to a cell or starvation.
In what situations is apoptosis necessary?
Apoptosis is necessary when cells are damaged and could be mutated, and when there are too many cells for organ structure.
How is apoptosis regulated?
Apoptosis is regulated by signals such as hormones and DNA damage, and a signal transduction pathway that results in apoptotic processes.
Mitosis adds cells to organisms, and apoptosis removes them. Under normal circumstances these processes are balanced so as to benefit the organism as a whole. In the next section we will examine what happens when this balance is disturbed and cell production runs out of control.