Question: how do you tell if a cell is dying

Andrew Devitt answered on 17 Jun 2013:

Well there are different types of cell death. One is good for us and this is called apoptosis (pronounced ‘app-oh-toe-sis’). This is where we the cell commits suicide and is removed quietly. This is how we get rid of cells that have got potentially dangerous mutations in their DNA (that we can’t repair). It’s also how we get rid of immune system cells that might attack ourselves.

We can spot this sort of death quite easily. All the DNA squeezes together and gets condensed and chopped up. The membrane undergoes a process called ‘zeiosis’ where the membrane looks as though it is boiling! We can also use some biochemical tests to look for cell death – these include looking for activation of some enzymes (called caspases) that help to dismantle the dying cells. And we can also look for changes on the cell membrane – here the cells that are dying expose signals. They are kind of like ‘adverts’ that say “I’m dying, eat me!”…… other healthy cells then eat the dying cell. All nice and quiet and quick (but a little cannibalistic). But the cells don’t get leaky through this death. Unlike the other form of death…….

which is accidental and unwelcome and harmful. This is called ‘necrosis’ and it is where the cells pop and spew their guts all over the body (and that’s not good). This is the sort of damage you do to your cells when you burn yourself or give some other ‘insult that is so great the cells can’t respond because they are killed. You could watch this happening down a microscope….. if you put some cells on a dish and look at them but add water…… by osmosis, the cells fill with water and pop.

So what’s wrong with cells popping? Well, there are things inside your cells that are meant to be hidden in cells and if they aren’t hidden, your body can see them and mount an immune response to them……. that means disease! Called autoimmune disease where your body attacks itself. Not good!