Final answer:
MPTP and rotenone are inhibitors that target Complex I (NADH-coenzyme Q oxidoreductase or NADH dehydrogenase) in the mitochondrial electron transport chain, blocking the transfer of electrons and disrupting energy production.
Step-by-step explanation:
In mitochondria, MPTP and rotenone are known inhibitors of Complex I of the electron transport chain. Complex I, also known as NADH-coenzyme Q oxidoreductase or NADH dehydrogenase, is the first enzyme complex in the chain where the electron transport begins. When an NADH molecule donates two electrons to Complex I, these are transferred to ubiquinone (also named coenzyme Q or Q), which becomes reduced to QH2. MPTP and rotenone interfere with this process by inhibiting the transfer of electrons from NADH to ubiquinone, effectively stopping the electron transport chain at the first complex.