Cellular Respiration

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Cellular Respiration
2010-10-28 00:09:36

cellular respiration
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  1. Chemical equation for cellular respiration
    + energy
  2. Explain why cellular respiration is an axample of a redox reaction.
    • -carbon being oxidized
    • - electrons are in sugar molecule are spending alot of time around carbon ( electrons closer to C than H b/c of electronnegativity )
    • - Oxidation: when H is shifted away from the part oc in CO2
    • - Oxygen becomes part of O in H2O, electrons in covalent bond shifts towads the O ( reduction )
    • - no electrons being transferred, only shifting
  3. Define Substrate level phosphorylation.
    • type of chemical reaction that results in the formation and creation of adenosine triphosphate (ATP) or guanosine triphosphate (GTP)
    • - adding phosphate

  4. Define Oxidative phosphorylation.
    is a metabolic pathway that uses energy released by the oxidation of nutrients to produce adenosine triphosphate (ATP)
  5. Name the 2 coenzymes involved in oxidative phosphorylation.
    what are thier functions?
    NADH : coenzyme found in all living cells

    FADH: organic molecule, non protein, vitamins
  6. What is the role of the electron transport chain in oxidatative phosphorylations?
    • carries electron from one protein to another
    • - loses energy in the process, the loss energy is used to produce ATP
  7. Explain why FADH2 produces only 2 ATP while NADH produces 3 ATP.
    • it has to do with where the electrons are dropped off
    • - NADH drops off at a higher energy level ( 3ATP)
    • - FAHD2 drops off at a lower energy level (2ATP)
  8. explain why oxygen is the "final acceptor" of the electrons in oxidative phosphorylations.
    b/c oxygen has the highest electronegativity
  9. how is most of the ATP in cellular respiration formed?
    in the oxidative phosphorylation
  10. What is Glycolysis?
    is the partial "breakdown" of "sugar" into pyruvate to generate ATP.
  11. Why is glycolysis the most ancient metabolic pathway?
    in prokaryates billions of years ago, no oxygen required, in cytosol
  12. Glucose priming stage.
    • when 2 ATP molecules are used to phosphorylate a glucose molecule
    • to make it ready; activate it for chemical reactions
  13. Glucose Splitting stage.
    when the phosphorylated sugar is split to form two 3 carbon molecules called Glyceraldehyde phosphate.
  14. ATP generation stage.
    converts the two Glyveraldehyde phosphates into two 3 carbon Pyruate molecules

  15. How many ATP are formed in glycolysis in the absence and presence of oxygen?
    Absence: 4ATP ( substrate level phosphorylation ) - 2ATP ( used in priming stage ) = 2ATP

    Presence: 2NADH *(times) 3ATP/NADH = 6+2 = 8 ATP
  16. How is Acetyl-CoA formed?
    The acetyl group combines with coenzyme A (CoA) to form acetyl-CoA
  17. How is the acetyl groups formed?
    one of 3 carbons of the pyruvate is oxidized to form Co2 and a two-carbon molecule
  18. wht is the function of coenzyme A?
    " shuttle bus " to carry out the 2 carbon( acetyl group ) to the next stage( citric acid cycle )
  19. How many ATP are formed by each sugar molecule during acetyl-CoA formation in the presence of oxygen?
    2NADH *(times) 3ATP/NADH = 6 ATP

  20. Where does the citric acid cycle take place in eukaryotes and prokaryotes?
    Eukarytoes: in matrix of mitochondria

    Prokaryotes: in cytosol
  21. How does the citric acid cycle work?

    • Combines the 2 carbon acetyl group with a four carbon molecule ( called oxaloacetate) to form a six carbon " citrate" molecule
    • - A series of ractions reforms the oxaloacetate, and completely oxidizes the acetyl group into two carbon dioxide molecules.
  22. How many ATP are formed by each sugar molecule in the citric acid cycle in the presence of oxygen?
    • ( 3NADH *(times) 3ATP/NADH) = 9
    • (1FADH2 *(times) 2ATP/FADH) = 2
    • (1ATP/substrate level phos. ) = 1
    • = 12 *(TIMES) 2 = 24 ATP / glucose molecule
  23. explain how the electron transport chain forms ATP by oxidative phosphorylation.
    • when it loses all energy, final acceptor = oxygen -> most electronegative.
    • ATP made using hydrogen ion concentration difference
    • the teritary structure is changing
  24. Prokaryotes lack mitchondia. Where does oxidative phosphorylation occur in prokaryotes?
    in the plasma membrane
  25. Define Anaerabic respiration. Explain how some prokaryotes carry out respiration.
    • - electron chain is not shut off
    • - use sulphate instead SO4 = final acceptor
  26. How many ATP are formed by each sugar molecule by substrate level phosphorylation?
    2ATP for Glycolysis and 2 for citric acid
  27. How many ATP are formed by each sugar molecule by oxidative phosphorylation?
    • Glycolysis= 2NADH times 3ATP/NADH = 6ATP
    • Acetyl CoA= 2NADH times 3ATP/NADH= 18ATP
    • Citric acid cycle= 6NADH times 3ATP/NADH = 18ATP
    • 2FADH2 times 2ATP/FADH2
    • = 34 ATP
  28. how efficient is cellular respiration?
    • very efficent 40% of energy of sugar molecule
    • - 38 ATP of oxidative phos. and sustrate level phos.
    • - 60% went to generating heat
  29. How are fats broken down in cellular respiration.
    • Fatty acids break off leaving 3 carbon backbone
    • -> goes into glycolysis
  30. how are proteins broken down in cellular respiration.
    • directly through kidneys
    • they are deaminated which = NH4 ( ammonia ) is then converted to urea or detoxified in liver
  31. what is fermentation?
    the partial breakdown of glucose in the absence of oxygen
  32. Where does fermentation take place?
    in cytosol of cell; outside mitochondria
  33. How many ATP are formed by each glucose molecule using fermentation?
    substrate level phosphorylation - 2ATP
  34. what happens to the electrons of the NADH formed during glycolysis?
    recycled vitamins in cytosol
  35. what is alcohol fermenation?
    • occurs in yeast, and involves the oxidization of one of the carbons of pyruvate to form CO2,
    • and the reduction of the remaining 2 carbon molecule using NADH to form ethanol
  36. what are some commerical uses for end products of alcohol fermentation?
    -bread, ethanol - waste material of yeast, wie, champagne bottles
  37. what is lactic acid fermentation?
    occurs in fungi and bacteria, and involves the reduction of pyruvate directly using NADH to form ethanol.
  38. what are some commerical uses for lactic acid?
  39. explain how muscle cramps occur.
    • decrease the pH of muscle cells, denaturate the proteins ( actin, myosin )
    • - cause by lack of oxygen to muscle- mitochondria shuts off