Lecture_23_2011_Nov14 - H 2 S + CO 2 (CH 2 O) +2S+H 2 O...

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Introduction to Biophysics Lecture 23 Photosynthesis
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Chlorophylls trap solar energy Formula: Magnesium porphyrin Phytol Polyen Absorption spectra: Chlorophylls a and b complement each over in absorbing the incident sunlight
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Light intensity Rate of photosynthesis PHOTOSYNTHESIS can be separated into light and dark reactions Rate of Photosynthesis vs. light intensity: 1932 R. Emerson/ W. Arnold In Chlorella cells at saturating light flash Only one O 2 evolve per 2500 Chl !!
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1932 R. Emerson/ W. Arnold In Chlorella cells at saturating light flash Only one O 2 evolve per 2500 Chl !! Concept of Photosynthetic Unit Time scale: ps (10 -12 sec) All Chls absorb light, but only a small portion of them, those at Reaction Center, mediate the transformation of light to chemical energy.
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O 2 evolved in PHOTOSYNTHESIS comes from H 2 O H 2 O + CO 2 (CH 2 O) +O 2 (green plants) 2
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Unformatted text preview: H 2 S + CO 2 (CH 2 O) +2S+H 2 O (green sulfur bacteria) 1941 heavy 18 O isotope H 2 18 O + CO 2 (CH 2 O) + 18 O 2 Hill Reaction: Illuminated chloroplast 2H 2 O + 4Fe 3+ O 2 +4H + + 4Fe 2+ Oxygen evolution can occur without reduction of CO 2 . CO 2 can be substituted by artificial EA. Ones again confirmed that evolved O 2 comes from H 2 O. Primary event of photosynthesis is light activated transfer of an electron from one substrate to another Two light reactions interact in photosynthesis: The quantum yield of photosynthesis: I. Red drop II. Enhancement phenomenon Quantum yield of photosynthesis (O2 evolved per photon) ( <700 nm) light ( <680 nm) light Photosystems I and II have complementary role Photosynthetic membrane: Suggested reading: Glaser 2.2.3...
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This note was uploaded on 12/09/2011 for the course PHYS 570 taught by Professor Staff during the Fall '08 term at Purdue University-West Lafayette.

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Lecture_23_2011_Nov14 - H 2 S + CO 2 (CH 2 O) +2S+H 2 O...

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