BSC2010 RVC1198 Forum for Module 3

You will answer these questions using your own words. You won’t copy and paste from elsewhere because that only harms your own understanding. These questions are your best practice on how to apply the concepts from this module to new scenarios. Take it seriously so you can do well on the exams.

Questions for group discussion:

1. When you exercise, your muscles are using ATP to do the movements. Thus, the cell is doing cellular respiration in order to replace the ATP needed. A) Draw a series of diagrams showing the energy transfers that occur during exercise (include: ATP, muscle, heat, cell respiration, glucose). B) When we exercise, we produce a lot of heat, to cool us down, our body produces sweat. According to the laws of thermodynamics, where is the heat coming from? C) When we exercise to lose weight, where is that mass going (do we sweat it out, it turns into heat, becomes digestive waste, how do we eliminate it?)?
2. Cells use primarily two ways of storing potential energy: 1) as concentration gradients and 2) in molecules. A) Explain how energy can be stored in these two forms and how it can be used to do other work. B) Propose an analogy that can explain these forms of energy storage using everyday items.
3. You have been assigned to lead a lab that takes plant material and converts it into ethanol for fuel. The process relies entirely on enzymes that break down the cellulose into ethanol. How would each of the following factors affect the efficiency of your task: temperature, pH, enzyme concentration, substrate concentration, allosteric inhibitor, competitive inhibitor, allosteric activator? For each factor, explain what would happen if you double it and what would happen if you cut it in half.

   For the following questions (4-6), make a diagram summarizing the main steps in cellular respiration (glycolysis, pyruvate oxidation, Krebs cycle, electron transport chain, chemiosmosis, fermentation) indicating the inputs and outputs of each process. This diagram will help you answer the questions. See example of diagram here:

4. Based at the diagram you drew, answer the following questions: A) How much energy is harvested in glycolysis (use ATP and potential ATPs as metric)? B) When is the oxidation of the glucose molecule completed? Explain what indicated that. C) What part/component of the glucose molecule is used in the electron transport chain? D) How does the electron transport chain contribute to ATP production?
5. Cyanide poisoning causes a type of hypoxia by inhibiting cytochrome c oxidase, which is the very last protein in the electron transport chain. A) Explain how/why cyanide inhibition of cytochrome c oxidase interferes with cellular respiration. B) Does the cell have any alternative to keep glycolysis going? C) Explain the purpose of oxygen in respiration.
6. A) Explain what would happen to ATP production in a mitochondrion that has “leaky membranes”, which would allow protons to diffuse through. B) Explain how the proton gradient contributes to ATP production.