Answer: The enzyme involved sits in the inner mitochondrial membrane and feeds electrons to the transport chain.
- A ATP is generated directly through substrate-level phosphorylation in most observed cases under typical physiological conditions
- B The enzyme involved sits in the inner mitochondrial membrane and feeds electrons to the transport chain
- C Acetyl CoA condenses with oxaloacetate to begin the cycle according to standard texts in general clinical practice
- D Carbon dioxide is released as a byproduct of the reaction in standard reference material under most conditions studied
Correct answer: B. The enzyme involved sits in the inner mitochondrial membrane and feeds electrons to the transport chain
Explanation: Succinate dehydrogenase, unlike other Krebs cycle enzymes, is embedded in the inner mitochondrial membrane and directly passes electrons to FAD, linking the cycle to the electron transport chain as Complex II.
Aerobic respiration unfolds in three locations: glycolysis in the cytoplasm yields a small amount of ATP directly, the Krebs cycle in the mitochondrial matrix harvests electron carriers (NADH, FADH2), and the electron transport chain in the inner mitochondrial membrane uses those carriers to generate the bulk of the ATP, with O2 needed only at this final stage.
Concept context
Glycolysis, the Krebs cycle, the electron transport chain, fermentation, and the respiratory quotient. The cellular energy-release counterpart to photosynthesis.