Eli5: What’s the difference between a dead single cell animal and a live one?

Question

I get one is alive and moving but under the microscope they appear identical for all intents and purposes.

In: 6

Answer 1

Edit: a crappy microscope.

Answer 2

Cells are just bags of (very complicated) chemical reactions. Whether it’s a single cell animal or a huge multi-cell one, a bunch of chemical reactions are continuously happening to keep the cell alive. When those reactions stop, the cell dies (and other reactions may start, like decomposition).

You can’t directly see chemical reactions with a microscope so, at the moment of death, they look basically the same. Just like how a person who *just* died looks like an alive person who’s very still. But the chemical reactions that made them alive have stopped. Pretty soon things are going to start breaking down as other chemical reactions get going.