WJEC Biology for A2 Level: Revision Workbook

Q5 [AO1, AO2, S] The following diagram shows a stage in aerobic respiration: a) What is meant by the term oxidative phosphorylation? (1) ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... b) Explain why each NADH generates three ATP molecules, but FADH only generates two. (3) ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... c) Cyanide is a non-competitive inhibitor of the final proton pump in the electron transport chain. Suggest why exposure is fatal and inhibition is not overcome as elections and protons accumulate. (3) ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... inter-membrane space mitochondrial matrix NADH ATP synthetase ADP + Pi ATP 2e − 2H + 2H + 2H + NAD O 2 + 2e − + 2H + H 2 O 1 2 2H + 2H + 2H + 2e − 2e − 3.1 Importance of ATP and 3.3 Respiration | 19 Unit 3 Energy, Homeostasis and the Environment Copyright: Sample material