BSCI330 – Cell biology and physiology Fall 2009
LAB MANUAL – Lab Exercise #9
2009. BSCI330 Laboratory Manual. University of Maryland, College Park.
Cells born and die. While all cells are born by DNA replication followed by some sort of cell
division, there are many different ways a cell can die. These include apoptosis, anoikis, necrosis, mitotic
catastrophe, and autophagy.
One way these types of cell death are defined is by the morphological
changes to the cell.
In apoptosis, a type of programmed cell death, cells round up, pseudopods retract,
chromatin condenses, the nucleus fragments, and the plasma membrane loses its characteristic
controlled permeability and becomes leaky.
Anoikis is apoptosis induced by loss of attachment, so it has
In necrosis there is cytoplasmic swelling, rupture of the plasma membrane, dilation of
organelles and some chromatin condensation.
After failed mitosis cells will die by mitotic catastrophe.
These cells have either micronuclei due to uneven distribution of chromosomes or multi-nuclei.
autophagy, cells possess autophagic vacuoles that are destroying organelles, but there is not chromatin
, which comes from the Greek word for “falling off” of leaves from a tree, is different
from some other types of cell death such as necrosis, which may occur due to physical injury, in that the
cell actively participates in its own destructive processes.
As you learned in the second journal article,
apoptosis is induced either extrinsically or intrinsically.
Both pathways lead to activation of caspases and
an “apoptotic cascade” which leads to the destruction of the cell.
Apoptosis is a normal physiological
process that occurs during development of an organism and maintenance of tissue homeostasis (a
balanced number of cells).
At the latest stage, cells become “apoptotic bodies” which are engulfed by
Improper induction of apoptosis leads to problems such as neurodegenerative
Purposely inducing apoptosis in certain cells, such as cancer cells, can be a valuable tool in