Biology 1115 Chapter 9 part 2

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Biology 1115 Chapter 9 part 2
2013-10-24 14:45:36
Cellular respiration

cellular respiration
Show Answers:

  1. What is another name for the citric acid cycle and where does it take place?
    • krebs cycle
    • takes place within the mitochondrial matrix
  2. What is the function of the citric acid cycle?
    The cycle oxidizes organic fuel from pyruvate, generating 1 ATP, 3 NADH, and 1 FADH2 per turn.
  3. What is the total energy yield per glucose molecule in the citric acid cycle?
    • 2 FADH2, 2ATP, 6 NADH, 4 CO2
    • (everything's doubled)
  4. The citric acid cycle has ___ steps, each catalyzed by a specific enzyme.
  5. Briefly describe the eight steps in the citric acid cycle. (2)
    • The acetyl group of acetyl CoA joins the cycle by combining with oxaloacetate, forming citrate.
    • the next seven steps decompose the citrate back to oxaloacetate, making the  process a cycle.
  6. What do the NADH and FADH2 produced by the citric acid cycle do?
    They relay electrons extracted from food to the electron transport chain.
  7. What makes the citric acid cycle a cycle?
    the regeneration of oxaloacetate
  8. Citric acid cycle ___________ under anaerobic conditions.
    cannot function
  9. CoA is actually used in how many steps in the citric acid cycle?
    • two
    • acts as an agent to drive anabolic steo forward
  10. What happened to the carbons of acetyl CoA in the citric acid cycle?
    got turned in to CO2
  11. What happened in terms of redox reactions in the citric acid cycle
    Acetyl CoA fully oxidized, electrons got transferred to NADH+ and FADH2
  12. Following glycolysis and the citric acid cycle, what accounts for most of the energy extracted from food?
    NADH and FADH2
  13. Where does the electron transport chain take place?
    in the inner membrane of the mitochondria
  14. How do the carriers (proteins) in the electron transport chain alternate as the accept and donate protons?
    the carriers alternate reduced and oxidized states as they accept and donate electrons
  15. Electron drop in energy as they go down the chain and are finally passed to oxygen, forming ___________.
  16. What is a protein used in the electron transport chain?
  17. The electron transport chain generates how much ATP?
    no ATP!
  18. What is the electron transport chain's function?
    it's to break the large free-energy drop from the food to oxygen into smaller steps that release energy in manageable amounts.
  19. Electron transfer in the electron transport chain causes proteins to do what?
    causes proteins to pump H+  from the mitochondrial matrix to the intermembrane space.
  20. How does H+ then move back across the membrane into the mitochondrial matrix?
    by passing through channels in ATP synthase
  21. what is the function of ATP synthase?
    uses exergonic flow of H+ to drive phosphorylation of ATP
  22. What is example of chemiosmosis?
    the use of energy in H+ gradient to drive cellular work.
  23. What was the net energy yield from the oxidative phosphorylation (per glucose molecule)?
    about 34
  24. Each pair of electrons released by NADH provides enough energy to produce how many ATP?
    about 3
  25. Each pair of electrons released by FADH2 provides enough energy to produce how many ATP?
    about 2
  26. The H+  gradient is referred to as a __________________.
    • proton-motive force
    • ATP synthesis occurs here
  27. In cellular respiration, what sequence does most energy flow?
    glucose-->NADH-->electron transport chain-->proton-motive force-->ATP
  28. What is the efficiency of cellular respiration?
    about 40%
  29. Before entering the pathway to cellular respiration, what happens to carbohydrates, amino acids, and fats?
    • carbohydrates: converted to glucose
    • Amino acids: deaminated
    • Fats: undergo beta oxidation
  30. What is required to keep glycolysis running?
  31. In the absence of oxygen, how is ATP produced?
    glycolysis couples with fermentation (anaerobic respiration) to produce ATP
  32. what does anaerobic respiration use instead of oxygen in the electron transport chain?
    an electron acceptor like sulphate
  33. Fermentation uses __________ instead of an electron transport chain to generate ATP.
  34. What are the two types of fermentation?
    • Alcohol fermentation
    • lactic acid fermentation
  35. What is alcohol fermentation? give an example.
    • pyruvate is converted to ethanol in two steps, while releasing CO2.
    • ex. used by yeast in baking
  36. What is lactic acid fermentation? give an example.
    • pyruvate is reduced to lactate to oxidize NAD+. no release of CO2
    • ex. used by bacteria to make cheese and yogurt
  37. What is a similarity between cellular respiration and fermentation?
    both process use glycolysis to oxidize glucose and other organic fuels into pyruvate
  38. What are the final electron acceptors in  fermentation and cellular respiration?
    • Fermentation: organic molecule (such as pyruvate)
    • Cellular respiration: oxygen
  39. What are obligate anaerobes?(2)
    carry out fermentation

    cannot survive in the presence of oxygen
  40. What are facultative anaerobes? Example?
    • they can survive using either fermentation OR cellular respiration
    • yeast and many bacteria