Study Guide 9
Last revised: Wednesday, March 6, 2002
Topic: Cell Energetics and Respiration
Chapter 9.

This is in some ways the most difficult chapter in this section of the course.

  1. Be able to recognize the structure of ATP, ADP, and AMP (see fig. 6.6). Why is ATP so useful in cell metabolism?
  2. What are “redox reactions”? Why are they important in biology?
  3. Explain why removal of a hydrogen atom (H) is called an oxidation. Where’s the electron? (Hint: what is a hydrogen atom made of?)
  4. What is the difference between an electron carrier and a terminal electron acceptor? Give examples of each.
  5. What does NAD+ do in biological systems? Relative to other biological molecules, how much NAD+ is there in a cell? Choose from: (a) a lot; (b) comparable to the concentration of amino acids; (c) extremely little. What happens to a cell when all its NAD+ becomes reduced to NADH? How can the cell get more NAD+? What happens to the hydrogen atoms?
  6. Be familiar with the process by which cells break down glucose sugar (glycolysis followed by respiration). How much energy does this process yield aerobically? anaerobically? How efficient are these two processes?
  7. Where does glycolysis occur? What are the end products? How many oxidation reactions are involved?
  8. What does the TCA (Krebs) cycle accomplish? What is the starting material? What are the final products?
  9. How is a mitochondrion organized? Be able to identify the matrix, the cristae, and the intermembrane space in which H+ ions accumulate during proton gradient formation. What kinds of molecules make up the electron transport chain? Where do electrons entering this chain originate? Where do they end up?
  10. What is a proton gradient? How is it generated? Once made, how can a cell use it to make ATP? What is the role of ATP synthase?
  11. Note that the term “chemiosmosis” refers to the coupling of enzyme reactions to the generation of transmembrane proton gradient. Are the terms “chemiosmotic phosphorylation” and “oxidative phosphorylation” interchangeable?
  12. What is meant by the term “fermentation”? Identify two organisms that can ferment. Identify two characteristic fermentation products. Are these edible? Identify common food/beverage in which you would find each of these two products.
  13. Contrast fermentation with respiration in each of the following respects: (1) what happens to electrons in NADH? (2) how efficient is the process? (3) where do the electrons made available in oxidation reactions wind up?


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