Biology 1115 chapter 9

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Biology 1115 chapter 9
2013-10-23 17:22:37
Cellular respiration

cellular respiration
Show Answers:

  1. What do living cells require from the outside source?
  2. Energy flows into a ecosystem as _______ and leaves as __________.
    • sunlight
    • heat
  3. Cells use chemical energy stored in organic molecules to _____________.
    regenerate ATP, which powers work
  4. What would "denotation" of our food molecules be?
    highly destructive and highly wasteful
  5. What's the point of cellular respiration? (2)
    • allows for the controlled, gradual release of energy
    • allows for energy to be harnessed to perform work
  6. what does the multi- step nature of cellular respiration allow?
    allows the diversion of molecules into other pathways when the cell has sufficient energy.
  7. Is cellular respiration a catabolic or anabolic pathway?
    catabolic pathway
  8. Is cellular respiration endergonic or exergonic?
  9. The __________ during chemical reactions releases energy stored in organic molecules. What is this released energy mainly used for?
    • transfer of electrons
    • this released energy is ultimately used to synthesize ATP
  10. Chemical reactions that transfer electrons between reactants are called?
    Redox reactions
  11. What is oxidation?
    A substance loses electrons, or is oxidized.
  12. What is reduction?
    A substance gains electrons, or is reduced.  (the amount of positive charge is reduced)
  13. The electron donor in a redox reaction is?
    reducing agent
  14. The electron acceptor in a redox reaction is?
    oxidizing agent
  15. What is generally oxidized and reduced in cellular respiration?
    • the fuel (such as glucose) is oxidized
    • oxygen is reduced
  16. Electrons from organic compounds are first transferred to?
    NAD+ which is a coenzyme.
  17. What is the function of dehydrogenase?
    It removes a pair of hydrogen atoms  (2 electrons and 2 protons) from the substance and transfer them to NAD+
  18. What is NAD+?
    • is an electron acceptor
    • functions as an oxidizing agent during cellular respiration
  19. What is NADH? (3)
    • Reduced form of NAD+
    • represents stored energy(potential energy) that is taped to synthesize ATP  
    • function is to pass the electrons to the electron transport chain
  20. How does the electron transport chain work?
    it passes electrons in a series of steps instead of one explosive reaction.
  21. What is at the end of the electron transport chain? what does it do?
    • oxygen is at the end
    • it pulls electrons down the chain in an energy-yielding tumble
    • the energy yielded is used to regenerate ATP
  22. What is the process that generates most of the ATP in cellular respiration called? Why?
    • Oxidative Phosphorylation
    • because is it powered by redox reactions
  23. What are the other two minor processes that forms small amounts of ATP?
    is formed in glycolysis and the citric acid cycle by substrate-level phosphorylation
  24. What are the three stages of cellular respiration in order? Describe them briefly.
    • Glycolysis: breaks down glucose into two molecules of pyruvate
    • Citric Acid Cycle: completes the breakdown of glucose into CO2
    • Oxidative Phosphorylation: accounts for most of the ATP synthesis
  25. In glycolysis, what happens to the glucose?
    It's broken down into two molecules of pyruvate, which has 3 carbons
  26. Where does glycolysis occur and what are the two major phases?
    • glycolysis occurs in the cytoplasm
    • two major phases: energy investment phase, energy payoff phase
  27. What is the function of phosphofructokinase PFK? (2)
    • is an enzyme that adds phosphate groups in the third step
    • controls the rate of glycolysis and is regulated by AMP and ATP
  28. What is the fourth step in glycolysis?
    • glycolytic step
    • molecule is broken down into two pieces at this step and everything is multiplied by 2.
  29. What does glycolysis NOT produce?
    • CO2
    • produces very little energy
  30. Glycolysis is technically anaerobic, which means?
    doesn't require energy
  31. What is the net energy yield from glycolysis?
    • 2 ATP
    • 2 NADH
    • 2 Pyruvate
  32. In the presence of ________, pyruvate enters the mitochondria
  33. Before the citric acid cycle can begin, pyruvate must be converted to ___________, which links the cycle to glycolysis.
    acetyl co A
  34. Where does the transition step take place?
    between cytoplasm and mitochondria
  35. What happened to the carbons of pyruvate in the transition step?
    got converted to acetyl Co A and CO2
  36. What happened to the electrons of pyruvate in the transition step?
    release in energy of NAD+ to form NADH
  37. What was the net energy yield from the transition step? (per glucose molecule)
    2 NADH