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PHOTOSYNTHESIS

PHOTOSYNTHESIS. Sun Hwa Dong. Photosynthesis. Produces organic substances Uses light Energy, Simple inorganic substances Light Energy to Chemical Energy. Absorption of Light. Sunlight = White light, but made up of wavelengths like red, green, blue Pigments absorb lights

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PHOTOSYNTHESIS

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  1. PHOTOSYNTHESIS Sun Hwa Dong

  2. Photosynthesis • Produces organic substances • Uses light Energy, Simple inorganic substances • Light Energy to Chemical Energy

  3. Absorption of Light • Sunlight = White light, but made up of wavelengths like red, green, blue • Pigments absorb lights • Red, Blue > Green • Green light cannot be reflected

  4. Absorption of Energy • Some used to produce ATP. • Some split water molecules – Photolysis of Water • This forms Oxygen and Hydrogen.

  5. CO₂ is absorbed to make organic substances. • Carbon in a gas to carbon in solid compounds – Carbon Fixation • This involves use of Hydrogen from photolysis and Energy from ATP.

  6. Measuring Rates of Photosynthesis • Production of O₂ : Aquatic plants release bubbles of O₂ • Uptake of CO₂ :If CO₂ is absorbed from water, the pH of water rises • Increases in biomass : the rate of increase in biomass means more photosynthesis.

  7. Effect of Light Intensity

  8. Effect of CO₂ Concentration • Low light intensity - shortage of ATP and hydrogen

  9. Effect of Temperature • CO₂ fixation is catalyzed by enzymes.

  10. Limiting Factors • Each factors can limit the rate when below optimal level. • Combination of factors – only one factor furthest from its optimum limits • When 2 of the factors are equally close to optimum, increasing them rises the rate.

  11. Action and Absorption Spectra • Action Spectra: % use of wavelengths of light in photosynthesis • Absorption Spectra: % use of the wavelengths of visible light that are absorbed

  12. Photoactivation • Chlorophyll & accessory pigments -Photosystem • Chlorophyll molecules in photosystem absorb light energy and pass it to 2 special chlorophyll molecules in the reaction centre. • Electron within the molecules become excited and photoactivated.

  13. Photophosphorylation • Photophosphorylation: the production of ATP, using E from light which is carried out by thylakoids • Thylakoids: regular “stack” of membranes that contain Photosystem I &Ⅱ, ATP synthase, a chain of electron carriers

  14. Chemiosmosis • Protons pass across membrane and release E which is used by ATP synthase to produce ATP. • The coupling of ATP synthesis to electron transport via a concentration gradient of protons → CHEMIOSMOSIS

  15. Chloroplasts structure • Chloroplast envelop • Thylakoids • Small fluid filled spaces inside Thylakoids • Mostly have stacks of thylakoids called grana • Colorless fluid around Thylakoids = stroma

  16. Bibliography • Course Companion p95-108 • Study Guide p21, p75,p76-81 • Pearson: p 74-78, p227-236 • http://biotransitioneng.wordpress.com/2009/05/10/fossils-fuels-%E2%80%93-a-great-problem/ • http://botit.botany.wisc.edu/images/130/Chlorophyta/Eremosphaera_Images/Chloroplasts_MC.html • Pearson Education, Inc., publishing as Benjamin Cummings • http://www.cbu.edu/~seisen/Photosynthesis.htm • http://helpmyphysics.co.uk/wordpress/?m=200902 • http://botit.botany.wisc.edu/images/130/Chlorophyta/Eremosphaera_Images/Chloroplasts_MC.html • http://generalhorticulture.tamu.edu/lectsupl/physiol/physiol.html • http://fhs-bio-wiki.pbworks.com/Factors-effecting-the-rate-of-photosynthesis • http://reefbuilders.com/2010/08/23/chlorophyll-f-a-newly-discovered-photosynthetic-pigment-uses-infrared-light/ • www.theoremeinnovation.com/revolution-en.html • www.firstrays.com/plants_and_light.htm • http://image.absoluteastronomy.com/images/encyclopediaimages/c/ch/chemiosmosis1.png • www.cbs.dtu.dk/staff/dave/roanoke/bio101ch07.htm • micro.magnet.fsu.edu/.../chloroplasts.html

  17. Vocabulary • Photosynthesis: The process used by plants and other organisms to produce all their own organic substances (food), using only light energy and simple inorganic substances. • Photolysis of water: Splitting of water by energy absorbed by chlorophyll. • Carbon Fixation: The conversion of carbon in a gas to carbon in solid compounds. • Photosystem: protein complexes involved in photosynthesis • Photoactivation: The initial stage of photosynthesis in chlorophyll Molecules where the presence of light Energy raises the energy. • Chemiosmosis: The coupling of ATP synthesis to electron transport via a concentration gradient of protons • Photophosphorylation: the production of ATP, using E from light which is carried out by thylakoids • Thylakoids: regular “stack” of membranes with very small fluid-filled spaces inside that contain Photosystem I &Ⅱ, ATP synthase, a chain of electron carriers • Grana: stacks of thylakoids • Stroma: a colorless fluid around the thylakoids that contains many different enzymes

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