What would happen to the concentrations of Pyruvate, NADH and intermembrane H+ if the ETC stopped working?

"Proton decreases" would be the right approach.

Explanation:

Thus, they aren't used for the transportation chain of electrons. This is also why protons have not been discovered to be injected towards intermembrane space.

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garbage disposal because lysosomes dispose of old cell parts like garbage disposals dispose of old food.