As an EMT, I have been taught to give oxygen to patients experiencing a wide range of problems, from respiratory issues like COPD and asthma, to traumatic injuries from car crashes or falls. And in my prior biology courses, I had learned the chemical equation for cellular respiration: C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O + Energy. However, I had not learned why specifically oxygen is needed for life and how/where it is used.
Now, I have learned that oxygen is consumed at complex 4 of the electron transport chain. Here, it is reduced to water, while protons are pumped against their gradient into the intermembrane space of the mitochondria. The proton gradient is then used by ATP synthase to produce ATP.
Learning about the electron transport chain in detail has also allowed me to understand how cyanide poisoning works. Cyanide binds to complex 4, preventing the reduction of oxygen (and the subsequent production of ATP). This explains why patients who have inhaled cyanide still have a high blood oxygen concentration, since it is unable to be used for ATP production. It has been interesting to learn in depth the biochemistry behind the conditions taught in my EMT training.
I really enjoyed reading your reflection because you explained the EMT perspective in a way that connected directly to what we learned about the electron transport chain. I thought it was especially interesting how you described the role of oxygen at complex IV, learning that it’s the final electron acceptor. It was a great way to show how biochemistry ties back to situations you see in EMT training.
Your connection between oxygen therapy and its exact role at complex IV really highlights how biochemistry deepens clinical understanding. I especially like how you tied cyanide poisoning to the ETC and explained how people exposed to cyanide will still have plenty of oxygen in the blood, but their cells won’t be able to use it. It’s always nice to later learn the molecular details behind situations you may encounter as an EMT (though hopefully you won’t have a patient with cyanide poisoning anytime soon).