Bio I Exam 3 Chapter 9

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  1. What is the primary source of energy of cell
    The sun
  2. What do the terms oxidation and reduction refer
    • Oxidation is the loss of electrons. Reduction is
    • the gain of electrons
  3. What kind of reactions are responsible for
    metabolism? What catalyzes these reactions? What happens to the electrons
    • Metabolism is a series of exergonic, redox
    • reactions catalyzed by enzymes. High energy electrons are transferred to
    • low-energy states
  4. Describe the process of a redox reaction.
    • A high electron donor (reducing agent) is
    • oxidized when it transfers electrons to an electron acceptor (oxidizing agent)
  5. What are the electron donors involved in cell
    respiration? What are they oxidized to? For photosynthesis?
    • Organic molecules are oxidized to CO2 in
    • respiration. In photosynthesis, H20 is oxidized to O2
  6. What are the electron acceptors involved in cell
    respiration? What are they reduced to? For photosynthesis?
    • O2 is reduced to H2O in respiration. In photosynthesis,
    • CO2 is reduced to macromolecules
  7. What is the organelle responsible for
    photosynthesis? What is the primary product of photosynthesis? What is the
    byproduct of this process?
    Chloroplasts; ATP; Oxygen
  8. What organelle is responsible for respiration?What is the primary product of respiration? What is the byproduct?
    Mitochondria; ATP; H2O
  9. What is the electron carrier of photosynthesis?
    NADPH (think of P for plants); NADH
  10. What in metabolism drives ATP synthesis?  What sets this up?
    • H+ gradient; electron transport chain sets up
    • the H+ gradient
  11. Photosynthesis and respiration are similar in
    that both use an ___________ 
    (exergonic/endergonic) step-wise energy release from ________ (high/low)
    energy electrons to drive synthesis.
    Exergonic, endergonic
  12. What is the primary source of energy in
    photosynthesis? In respiration?
    Light energy; chemical energy
  13. What is broken down by respiration? What is
    Organic molecules; ATP and Heat
  14. What is the electron receptor in aerobic
  15. What is the difference between aerobic
    respiration and anaerobic respiration?
    • Aerobic respiration uses oxygen and anaerobic
    • respiration does not use oxygen
  16. What is a predominant source of chemical energy?
    • Molecules with lots carbon and hydrogen (organic
    • molecules)
  17. What happens when electrons are transferred?
    • Energy is released which is used to do work and
    • make ATP
  18. What kinds of organisms make use of aerobic respiration?
    • Both prokaryotes and eukaryotes, most large
    • organisms, humans
  19. Why aren’t electrons directly released to reduce
    oxygen? How are they released?
    • The direct combination would be explosive.
    • Instead, electrons are passed down an electron transport chain from NADH to
    • oxygen in a stepwise function. Potential energy is lost along the way.
  20. How many molecules of ATP are produced from one
    glucose molecule in aerobic respiration?
    30-38 ATP
  21. What are the four different steps of aerobic
    respiration? What is the basic function of
    • Glycolysis – 6 carbon glucose molecule is broken
    • down into two 3-carbon molecules; pyruvate oxidation – 3-carbon molecule
    • oxidized to 2-carbon molecule and CO2 is exhaled; citric acid cycle – 2-carbon
    • molecule made into CO2; electron transport chain – electrons from previous 3
    • steps used to drive ATP synthesis, O2 accepts final electron to form H2O
  22. Where do the different steps of aerobic
    respiration take place?
    • Glycolysis happens in the cytosol, the others
    • take place within the mitochondria
  23. What sources of chemical energy are used as
    electron receptors in respiration?
  24. What do the energy molecules NADH and FADH2
    stand for?
    • Nicotinamide adenine dinucleotide; flavin
    • adenine dinucleotide
  25. What happens in the investment stage of
    • A glucose molecule is phosphorylated twice by
    • ATP and becomes fructose biphosphate. The fructose biphosphate is then split
    • into two phosphorylated 3-carbon molecules
  26. What are the products from the investment phase
    of glycolysis? Which one is used further? What happens with the other one?
    • Dihydroxyacetone phosphate and Glyceraldehyde
    • 3-phosphate (G3P). G3P is used further; Isomerase can convert dihydroxyacetone
    • phosphate into G3P as the equilibrium shifts
  27. What happens in the energy payoff phase of
    • Glyceraldehyde 3-phosphate dehydrogenase (GAPDH)
    • catalyzes the removal of electrons to form NADH from NAD+ and phosphorylate
    • G3P. Phosphoglycerate kinase then catalyzes the transfer of a phosphate group
    • to ADP to form ATP. Pyruvate kinase then transfers the second phosphate group
    • to another ADP to form another ATP molecule
  28. What is the final product from the energy payoff
    phase of glycolysis? What is it’s chemical composition? How many ATP molecules
    are produced from the process?
    Pyruvate; a carboxyl, , and hydrocarbon; 2
  29. Is glycolysis a net endergonic or exergonic
    Exergonic, although parts of it are endergonic
  30. What happens in the pyruvate oxidation phase?
    • It enters the mitochondria. The carboxyl group
    • is removed to form CO2 and electrons are removed to form NADH. The acetyl group
    • then attaches to the sulfur atom of coenzyme A
  31. Citrate acid is formed when what two molecules
    come together?
    • Acetyl (after shedding COA) and 4-carbon
    • oxaloacetate
  32. What happens to the carbon molecules of citrate
    acid as it moves through the citric acid/krebs cycle?
    • 2 carbons are removed as CO2 and 4-carbon
    • oxaloacetate is reformed
  33. What happens to electrons of the citrate acid
    molecule as it passed through the citric acid/Krebs cycle?
    • They are removed to form 3 NADH molecules and 1
    • FADH2 molecule
  34. CoA is removed at the beginning of the citric
    acid/Krebs cycle but reappears later in the cycle. What does it attach to and
    why does it reappear?
    • It attached to 4-carbon succinyl to aid in
    • phosphorylation and help form ATP or GTP
  35. What products and how many of each are produced
    in the citric acid/Krebs cycle?
    3 NADH, 1 FADH2, 1 ATP or GTP, 2 CO2
  36. How are fats transformed into energy?
    • 2 carbons are removed from the fatty acid which
    • are then turned into an acetyl group in a process that also yields NADH and
    • FADH2. The acetyl group then attaches to CoA and enters the citric acid/Krebs
    • cycle.
  37. Why do fats have high caloric content?
    • They contain lots of carbon and can make lots of
    • acetyl groups which then go on to be processed and create energy in the citric
    • acid/Krebs cycle
  38. What is the net change in free energy from the
    respiration of one glucose molecule? Order steps from most energy to least
    energy used
    • About -700; Citric acid cycle, pyruvate
    • oxidation, glycolysis
  39. Where do the different phases of respiration
    take place?
    • Glycolysis takes place in the cytosol, pyruvate
    • oxidation and citric acid/Krebs cycle take place in the matrix of the
    • mitochondria, electron transport chain takes place in the cristae of the
    • mitochondria
  40. What is the electron transport chain in
    respiration made from and where is it located?
    • It is a chain of proteins located on the inner
    • mitochondrial membrane (cristae)
  41. What molecules donate electrons to the electron
    transport train in respiration? Where are they delivered to? What happens to
    • NADH and FADH2; membrane proteins; they are
    • energized to perform active transport a proton against the gradient
  42. Where does a high proton concentration
    accumulate during cellular respiration?
    In the intermembrane space of the mitochondria
  43. What membrane proteins are mostly responsible
    for the transport of electrons in respiration?
    Cytochromes and others that contain iron
  44. What acts as the final electron acceptor in
    cellular respiration and what does it form once it accepts the electrons?
  45. What is the process of chemiosmosis and what
    does it do in respiration? What aids in this process and what is this made
    • Chemiosmosis is the facilitated diffusion of
    • protons back into the mitochondrial matrix and results in ATP production. ATP,
    • made from about 10 proteins, synthase is what helps the proton diffuse.
  46. What are the byproducts of each of the steps in
    cellular respiration?
    • Glycolysis = 1 ATP and 1 NADH, Pyruvate
    • oxidation = 1 NADH and 1 CO2, Citric Acid Cycle = 3 NADH, 1 FADH2, 1 ATP, 2
    • CO2, Oxidative Phosphorylation = 15 ATP
  47. Where does ATP synthase occur in PROKARYOTES?
    On the Cell membrane using an ion gradient
  48. What is anaerobic respiration? Where does it
    occur? How is it similar/different than aerobic respiration?
    • Respiration without O2; prokaryotes; similar to
    • aerobic respiration but just with a different final electron acceptor
  49. What is fermentation?
    • It is a process to make ATP that includes only
    • glycolysis and sometimes pyruvate oxidation. It makes much less ATP than respiration
    • because it only includes substrate level phosphorylation
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Bio I Exam 3 Chapter 9
2013-10-22 21:52:20
Bio Exam Chapter

Bio I Exam 3 Chapter 9
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