Aerobic Glucose Metabolism

Assignment Module 7

The questions posed below are to be answered through the "Quiz" at the end of this module. Your responses are Due by 11:55 pm (EST) on 23 April. You may use the threaded discussions to discuss with your classmates as you like prior to answering. The quiz itself is not timed; you may take as long as you like. Only your first answer to each question is accepted as your response. You may find it helpful to formulate your responses in an external editor then copy and paste your responses to the "quiz".

  1. Discuss the role of the vitamins and minerals listed in the citric acid cycle enzymes. In which reactions are each one important? (Some are used in more than one enzyme).
  2. The overall rate of conversion of pyruvate to CO2 in the citric acid cycle; the rate of electron transfer in oxidative phosphorylation are coupled to the rate of used of ATP. Discuss these couplings. How is the rate of carbon metabolism connected to the rate of ATP use?
  3. All of the complexes involved in the oxidative phosphorylation system must be oriented the same way in the mitochondrial membrane. Experimentally, the orientation of the complexes can be randomized. The result is that no ATP is synthesized, but that O2 reduction (electron transport of NADH to O2) works at normal rates. Why is the absolute orientation of all of the complexes important to the synthesis of ATP but not to the electron transport?
  4. The fatty acid components of fats are dissembled into the 2 carbon units of acetyl CoA ( the same as the product of pyruvate dehydrogenase) which are then sent through the citric acid cycle. We learned last module that Glucose can be synthesized via gluconeogenesis from oxaloacetate the same molecule as the at the "start" of the citric acid cycle. Why then is it "common knowledge" that fats cannot be converted to glucose? (The common knowledge is mostly true this time). Why is it easy to convert sugars to fats?