Cyanide (C≡N−) blocks complex IV of the electron transport chain. Suggest a hypothesis for what happens to the ETC when complex IV stops working. Your hypothesis should explain why cyanide poisoning in humans is fatal.

Video transcript

Hi everyone here's our next question, which one is an incorrect statement about cyanide which is C. Triple bonded to an end and then attached to something. So let's look at our answer choices, noticing that choice D says all statements are correct. So there is a chance that we don't have an incorrect statement here. So, Choice A says a strong irreversible inhibitor of the respiratory oxidase enzyme. Well, this is true, cyanide is a strong irreversible inhibitor of cytochrome oxides. So irreversible, you can't um undo it once it's there inhibiting once it's there blocking this action, you can't remove it. It's not like sometimes you have an inhibitor that binds and then releases but not in this case. So irreversible inhibitor. So when it binds cytochrome oxidase is one of the complexes in the electron transport chain. So once it binds there and blocks it you just bring the whole electron transport chain to a halt. So we saw that choice A is correct. So I'm just gonna put a dot rather than eliminating it because we know we have the possibility that there might not be any incorrect statements here. Choice B says it blocks complex four of the electron transport chain. And that is true. We said that it blocks the complex an electron transport chain that happens to be complex four. So that's also correct. Then troisi cyanide poisoning in humans is fatal. And that is also true because once we've completely blocked this electron transport chain, we actually just shut down the whole pathway that is the major producer of A. T. P. In the cells. You shut down the whole aerobic respiration pathway and without sufficient production of A. T. P cells begin to die and you will eventually cause the death of the person. So cyanide poisoning is fatal because it completely shuts down in an irreversible way the electron transport chain leading to that major production of a teepee. So choice C also correct. So therefore we have no incorrect statement, so our answer must be Choice D. All statements are correct. So again, the question was which one is an incorrect statement about cyanide choice D. All these three statements were correct. See you in the next video.