system
Given the following post, respond as if you're commenting on Reddit:
human
Is cyanide toxic to all aerobic organisms?

Or not?

I know for sure that it's toxic to all organisms that have mitochondria (or an electron transport chain) - and cytochrome c (which cyanide blocks) is an integral part of the ETC. But it's not bleach (which practically destroys all living organisms). 

But what about aerobic bacteria? Do they use cytochrome c? I'm discussing this issue with NASA Astrobiologist Chris McKay, so he would be especially interested in the answer to this too.
gpt
all aerobic bacteria have cytochrome C. this is actually one way we test to see if something can use oxygen. we test colonies for having cytochrome C oxidase, the enzyme next in the chain after cytochrome c on the ETC.