Multiple Choice
In oxidative phosphorylation, how many electrons are donated by one molecule of FADH2 to the electron transport chain?
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Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation
Oxidative Phosphorylation 1
Multiple Choice
In oxidative phosphorylation, what is the relationship between the electron transport chain (ETC) and oxygen?
A
Oxygen donates electrons to Complex I to initiate electron flow through the ETC.
B
Oxygen directly phosphorylates ADP to ATP at ATP synthase.
C
Oxygen is pumped across the inner mitochondrial membrane by Complex IV to generate the proton gradient.
D
Oxygen is the terminal electron acceptor of the ETC; it accepts electrons (and protons) to form water.
Verified step by step guidance1
Understand the role of the electron transport chain (ETC) in oxidative phosphorylation: it is a series of protein complexes located in the inner mitochondrial membrane that transfer electrons through redox reactions.
Recognize that electrons entering the ETC come from electron carriers NADH and FADH2, not directly from oxygen.
Identify oxygen's role as the terminal electron acceptor at the end of the ETC, specifically at Complex IV (cytochrome c oxidase), where it accepts electrons and combines with protons to form water.
Note that oxygen does not donate electrons to Complex I, nor is it involved in directly phosphorylating ADP to ATP; ATP synthesis is driven by the proton gradient created by the ETC.
Summarize that oxygen's essential function is to maintain electron flow by accepting electrons, allowing the ETC to continue pumping protons and generating the proton motive force necessary for ATP synthesis.
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