The higher the altitude, the lower the oxygen level in air. Climbers of very tall mountains risk altitude sickness, which is an illness characterized by shortness of breath, weakness, dizziness, and confusion. The early symptoms of cyanide poisoning are the same as those for altitude sickness. Cyanide binds tightly to cytochrome c oxidase, the protein that reduces oxygen molecules in the final step of mitochondrial electron transfer chains. Cytochrome c oxidase with bound cyanide can no longer transfer electrons. Explain why cyanide poisoning starts with the same symptoms as altitude sickness.

In both cases, the person is deprived of ATP source as the aerobic cellular respiration comes to halt.

Explanation:

At higher altitudes, low oxygen pressure deprives the cells of oxygen to serves as the terminal electron acceptor. In the absence of molecular oxygen, electron transport from NADH and FADH2 to O2 can not generate the proton concentration gradient required for ATP synthesis.

Cyanide poisoning also stops ATP synthesis by inhibiting the electron transfer from cytochrome oxidase to oxygen. Cellular respiration is a source of ATP for living aerobic cells. In the absence of ATP synthesis, the person is deprived of energy sources and feels weakness, dizziness, confusion, and shortness of breath.