It consists of a series of molecules, most of them proteins called __. First one compound is __, then it is __ as it passes electrons to the next compound, which is __, and so on in a cascade. The electrons move from one compound to another down to the last moeclue, which is __. As the electrons move from one compound to another, they lose energy. All along the way, the __ in the cascade allow energy to be released in small enough amounts to be used by the cell.
- oxygen (final electron acceptor)
- redox reactions