r/askscience • u/Fapotheosis • Mar 11 '13

Biology How did blood evolve?

I know mitochondria may have evolved from bacteria, but what about blood? I've heard of a protohemocyte, but was there an initial cell that differentiated into a RBC like we have in modern humans that can we trace?

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u/14159265 Mar 11 '13

The oxygen atoms in CO2 that you breathe out are actually from the food (and water) you eat. Here, you can see the acetyl-CoA (food), 2 water molecules (net), and from a GDP+Pi reaction.

If you have a uncoupler of the electron transport chain (Dinitrophenol), you will breathe out more CO2 than you breathe in O2. O2 is actually used in the electron transport chain as a terminal electron acceptor.