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Photosynthesis

Photosynthesis. Photosynthesis: the process in which chloroplasts capture light energy from the sun and convert this light energy into chemical energy (stored in sugar/organic molecules) Autotroph : “self-feed” Ability to sustain themselves without eating other organisms

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Photosynthesis

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  1. Photosynthesis

  2. Photosynthesis: the process in which chloroplasts capture light energy from the sun and convert this light energy into chemical energy (stored in sugar/organic molecules) • Autotroph: “self-feed” • Ability to sustain themselves without eating other organisms • Make organic molecules from inorganic raw materials obtained from the environment (CO2, H2O, minerals) • Plants, protists, and prokaryotes • Biosphere producers

  3. Heterotroph: “other-feed” • live on compounds produced by other organisms (unable to produce their own food) • Biosphere consumer

  4. Parts of the Leaf • Chloroplasts are the sites of photosynthesis • All of the green parts of the plant which contain chlorophyll-green pigment (stem, unripe fruit, LEAVES) • Light energy is absorbed by the chlorophyll which drives the synthesis of food molecules in chloroplasts

  5. Chloroplasts are found mainly in the mesophyll(tissues in the interior of the leaf30 to 40 chloroplasts in one mesophyll cell)

  6. Stomata (stoma): site of gas exchange - CO2 in the leaf and O2 /water vapour out the leaf

  7. Roots: water is delivered to the leaves veins (xylem)and sugar is exported to the roots via the veins (phloem)

  8. Structures of a Chloroplast • Stroma: fluid within the chloroplast • Analogous to the ______of a mitochondrion • Thylakoid: flattened membranes that contains chlorophyll • Grana: stacked thylakoids • Analogous to the _______of a mitochondrion for more surface area

  9. Inside a chloroplast

  10. Chemical Equation 6CO2 + 6H2O + light  C6H12O6 + 6O2 Or reduced equation: CO2 + H2O + light  CH2O + O2

  11. Two Stages of Photosynthesis • Light reactions (photo) • Calvin cycle (synthesis) • Light Reactions: -occurs in the thylakoid of chloroplasts -light absorbed by chlorophyll drives a transfer of electrons and hydrogen from water to an electron acceptor NADP+

  12. -NADP+ temporarily stores energized electrons -water is split in the process and therefore the light reaction of photosynthesis gives of oxygen as a by product -NADP+ gets reduced (gains 2 electrons and an hydrogen ion) by solar power and forms NADPH  this generates ATP by powering a phosphate to ADP

  13. -This synthesis of ATP ( P + ADP ) is called photophosphorylation. ** Light energy is converted to chemical energy in the form of two compounds: 1. NADPH (energized electrons) 2. ATP (energy currency of cells)

  14. Calvin Cycle -also known as dark reactions or light independent reactions -YET occurs in the light because it is powered by ATP and NADPH which require light -process involves synthesis of sugar (carbohydrate) -occurs in the stroma(fluid)

  15. -Carbon fixation: incorporating CO2 from the air into an organic compound -the fixed carbon is then reduced (gains electrons) to form a carbohydrate -fixed carbon is able to be reduced due to the NADPH reducing power and ATP produced by the light reaction

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