: Hello all,
: I'm curious, for a creature that breathes Carbon Dioxide - what color would
: their blood be? Ours is Red, due to iron content and Oxygen/Nitrogen...
: but really I forget how Oxygen impacts our own blood color anyhow. It's
: been three years since Gr 12 Biology. : )
: Thanks,
: -Blayne [ernie]
Our blood is red because the iron in our hemoglobin is what lets it bind oxygen, and oxydized iron (rust) is red.
I've always figured green-blooded aliens who breath the same atmosphere as us probably have a copper-based hemoglobin-equivalent, as copper oxydizes green (see the statue of liberty).
AFAIK carbon dioxide is fairly inert, and plants only "breath" it in the sense that they use solar energy to rip the carbon out of it to build their cells with. (The leftover oxygen is a toxic by-product. We animals do the opposite process, oxydizing organic carbon compounds to release the stored energy from them). It wouldn't really work the same way as oxygen in as far as coloring some hypothetical CO2-breathing alien animal's blood.
