Reference no: EM133764714

Discussion Post: Biology

I. 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 it has used. (i) Draw a series of diagrams showing the energy transfers that occur during exercise (include: ATP, muscle, heat, cell respiration, glucose -- you need to make your own diagram you cannot copy from somewhere else). (ii) 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? (iii) 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?)?

II. Cells use primarily two ways of storing potential energy: (a) as concentration gradients and (b) in molecules. (i) Propose an analogy that can explain each these forms of energy storage using everyday items. (ii) Explain how energy can be stored in these two forms and how it can be used to do other work.

III. 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, inhibitor concentration? For each factor, explain what would happen if you increase it and what would happen if you decrease it.

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. Draw it in paper and upload a photo or scan, post it as an image embedded in the discussion post.

I. Based on the diagram you drew, answer the following questions: (i) How much energy is harvested during glycolysis (use ATP and potential ATPs as metric)? (ii) When is the oxidation of the glucose molecule completed? How could you tell? (iii) What part/component of the glucose molecule is used in the electron transport chain? (iv) How does the electron transport chain contribute to ATP production?

II. Cyanide poisoning causes a type of hypoxia by inhibiting cytochrome c oxidase, which is the very last protein in the electron transport chain. (i) Explain how/why cyanide inhibition of cytochrome c oxidase interferes with cellular respiration. (ii) Does the cell have any alternative to keep glycolysis going? (iii) Explain the purpose of oxygen in respiration.