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Photosynthesis – Part I Spring 2013 - Althoff Reference: Mader & Windelspecht Ch. 7) Lec 07 Photosynthetic Organisms Process of Photosynthesis
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Definitions Photosynthesis converts ____________ into the ________________ of a ________________ ____________ = photosynthetic organisms that produce their _______________ examples: ________________ ________________ ________________ Autotrophs = _______________
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Cyanobacteria Algae Plants _________________
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The opposite of AUTOTROPHS are… _______________ = ____________ …they cannot make their own food…aka ____________________ carbohydrates. Heterotrophs, as do autotrophs, use ___________________ produced by photosynthesis as a source of building blocks for growth and repair…as well as a source of chemical energy for __________ work.
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Birds, Fish, Mammals, etc. Fungi Insects Mussels _________________
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Photosynthesis by product…. Carry on ____________ ____________ Value to all organisms = ___
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O 2 bubbles from Elodea leaves
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Besides the O 2 “byproduct” of photosynthesis…there are other benefits to humans: Building materials (think lumber) Fabrics (think cotton) Paper Pharmaceuticals Aesthetic value (think flowers)
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Photosynthesis takes place in the “green” portions of plants (aka leaves) For flowering plants (most of what is on earth), ____________ tissue is present that specializes in photosynthesis. mesophyll
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Entry of raw materials for photosynthesis…. CO 2 in air enters through ________ H 2 O in soil enters through _______, then up ________ ______ (aka vein) CO 2 and H 2 O, once in the leaf, ________ into _______________ mesophyll Top of leaf
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Chloroplast Actual chloroplast ~37,000 x
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Chloroplast structure ___________ ___________: outer and inner __________ semi- fluid interior __________ – flattened sacs _______ (gramum pl.)– stacked thylakoids double membrane
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Grana close up…. thylakoid space thylakoid membrane independent thylakoid in a granum overlapping thylakoid in a granum
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Thylakoids Spacing of thylakoids thought to be connected to the ____________________ thylakoids within a chloroplast…. The result is a _________________ …providing a tremendous amount of surface area for photosynthesis to occur.
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Thylakoids and Stroma The __________________ actually contains the chlorophyll…and other pigments capable of absorbing solar energy. The ________ contains an energy-rich solution where CO 2 is first attached to an organic compound…then reduced to a carbohydrate.
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Photosynthesis: The Proce ss The equation implies that photosynthesis involves ________ (=oxidation- reduction)…and the movement of electrons from one molecule to another This means a) CO 2 gains an electron and b) H 2 0 loses one….a ____ is “transferred”
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Photosynthesis: The Process In photosynthesis, solar energy is used to generate the ___________________ the CO 2 to a __________________. Keep in mind, this carbohydrate represents the _______ produced by land plants, algae, and cyanobacteria that feeds _____ the biosphere.
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Two Important Coenzymes ________ is the coenzyme of oxidation- reduction active during photosynthesis. When reduced it accepts 2 electrons and and 1 hydrogen atom to become _______ When NADPH oxidizes, it give up its electrons NADP + + 2e - + H + NADPH
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Back to the Elodea leaf… What molecule supplies the electrons that reduce NADP + during photosynthesis? The _____________ _________________ that is split!
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Two Sets of Reactions _________________—so named because they only occur when solar energy is available. Associated with “_______” energy __________________________—named for Melvin Calvin who discovered the enzymatic reaction that reduces CO 2. Associated with “____________” energy
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LIGHT REACTIONS CALVIN CYCLE REACTIONS O2O2 CH 2 O
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Light Reactions Sunlight/solar energy __________ by chlorophyll that drives photosynthesis Solar energy “________” the electrons that move down an _________ _______________. As it does, energy released is captured as _____ molecules. Mader Fig. 6.12 p114
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Light Reactions To summarize…. Solar energy _________________ (ATP, NADPH) But, O 2 is given off, too O2O2
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Calvin Cycle Enzymes present speed up the reduction of CO 2 during __________________ Occurs in the ____________________ of the chloroplast stroma When reduction results in carbohydrate…it can later be converted to glucose…this is achieved by using ATP and NADPH _____ the light reactions
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Calvin Cycle Reactions To summarize…. _________ energy __________ energy (ATP, NADPH) (carbohydrate) CH 2 O
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