Hey everyone, so I've been thinking about this a lot lately after that brutal workout last week where I could barely catch my breath. What actually happens to pyruvate when there's hardly any oxygen around in the cell compared to when there's plenty of it floating about? Like, I remember feeling that burn in my legs and wondering if it's just the pyruvate doing something different without enough air getting to the muscles. Anyone got a clear picture of the switch between those scenarios? It's been bugging me since biology class ages ago.
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Yeah, that totally makes sense—I've pushed through those same anaerobic moments during runs and you can feel the difference right away. When oxygen is scarce, pyruvate usually gets turned into lactate in animals (or ethanol plus CO2 in yeast) so the cell can keep cranking out a bit of ATP through glycolysis without waiting around. But when there's plenty of oxygen, it heads into the mitochondria, gets converted to acetyl-CoA, and feeds into the Krebs cycle for way more energy. I always find it wild how flexible cells are. If you're trying to wrap your head around the whole pathway, I sometimes glance at this cellular respiration chart someone shared ages ago helps me visualize the branches better without overcomplicating it. Just my two cents from messing with it during study sessions.