Bio. Ch. 8 Photosynthesis

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Bio. Ch. 8 Photosynthesis
2012-02-26 20:16:10

Chapter 8 Bio
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  1. Photosynthesis definition:
    Process which energy of sunlight is used to fix/redue CO2 into organic compounds

    • Ability to make food using sunlight
    • Function: Produce sugars

    Photoautotrophs/half in ocean
  2. Equation for photosynthesis:
    6CO2+12H20 ---> C6H12O6 + 6H20 + 6O2

    CO2's reduced
  3. Overal procedure of Photosythesis:
    • 1.) cpature suns energy
    • 2.) makes ATP and NADPH (electron carrier like NADH)
    • 3.) uses ATP and NADPH to make sugar
  4. Where is photosyntheis occuring:
    (green parts) Chloroplasts
  5. Structure of a leaf:
    • CO2 leaves from Stoma
    • Stoma is made of guard cells that open and close (prevent H20 from escaping)

    • Parenchyma- generalized cell typ
    • eq: spongy parenchyma/palisade parenchyma
  6. Chloroplasts Figure:
    • inside thylakoids: photosystem...
  7. Photosystem:
    • Energy bounces around until it hits the reaction center

  8. C.B. Van Niel's Work
    • 1930's purple sulfur bacteria
    • using CO2 + 2H(S) ---light---> CH2O + H2O + 2(S)
    • S-sulfur
    • he predicted then maybe the general equation for photosyntheis is:
    • CO2 + 2H(some element)---> CH2O + H2O + 2(some element)

    • so by emplementing oxygen we get:
    • CO2+2HO--->CH2O+H2O+O2
  9. carbon fixation:
    the generated H+ ions and electrons by splitting water were used to convert CO2 into organic matter
  10. 2-stage process (photosynthesis)
    • a) light dependent reactions: uses suns energy to make ATP and NADH
    • b) light independent reactions: (non dependent on light)
    • -Calvin cycle
    • -uses ATP and NADH
  11. Radiant energy
    • light from sun (waves/packets)
    • waves = photons
  12. Length of light wave: (electromagnetic spectrum)
    • longe wave: little energy
    • short wave: higher energy
    • gamma rays (short/blue)----visible light---- radio waves (long/red)
  13. photosynthetic pigments:
    absorb light and use it for photosynthesis
  14. Chloryphyll
    • (green) reflects green light and absorbs other colors
    • -main pigment in plants
    • -in thylakoid membranes
  15. Types of chlorophyll:
    • chlorophyll a - main kind
    • chlorophyll b - accessory pigments- help out
    • chlorophyll c - " "
    • caratanoids - yellow,orange/accessory pigments
    • phycobiloproteins - red and blue (red algae)
  16. Absorption spectrum of a pigment:
  17. Action spectrum vs absorption spectrum
    • action is sum of all pigments (rate of photosynthesis)
    • absorbstion is single pigment
  18. NADPH
    • another electron carrier like NADH
    • light dependent reactions:
    • H2O+NADP+ADP+P ----light---> NADPH + O2 + ATP
  19. Pigments organized into:
    • Photosystems:
    • Photosystem I - reaction center
    • Photosystem II -
  20. Z scheme
    • Non cyclic (begin and ends) photophosphorulation = made ATP
  21. Calvin Cycle
    • makes sugar using ATP and NADPH (in stoma)
    • Steps:
    • 1) Carbon fixation
    • 2) Reduction
    • 3) Regeneraton of RuBP
    • For every 3 molecules of CO2 that enter= 1 molecule of G3P (sugar)
  22. Enzyme carries out reaction that incorporates CO2 into organic form:
    Rubisco is the enzyme that helps the carbon fixation reaction (very slow 3 substrates/sec)
  23. Photorespiration
    • RuBP (rubisco) combines w/ O2 instead of CO2 = sugar is lost if CO2 is low or temp is high.
    • @25degrees C 20% of photosynthetically fixed carbon is lost.

    Stoma is closed (hot environments)
  24. C3, C4, and CAM plants
    C3- plants use calvin cycle

    • C4- more efficient to capture CO2
    • no photoresperation
    • Stoma can be closed more
    • 4C sugars involved
    • C4 pathway and calvin cycle
    • (corn,grabgrass)
    • making of sugar w/o lots of CO2

    CAM plants: C4 and C3 pathways. two pathways in same cell but seperated in time. C4 at night.