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Photosynthesis

Photosynthesis. process by which plants, algae and some bacteria use light energy to convert inorganic compounds into organic compounds. Overall Reaction. light enzymes CO 2 + H 2 O → → → C 6 H 12 O 6 + O 2 Inorganic    Organic

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Photosynthesis

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  1. Photosynthesis process by which plants, algae and some bacteria use light energy to convert inorganiccompounds into organic compounds

  2. Overall Reaction light enzymes CO2 + H2O → → → C6H12O6 + O2 Inorganic   Organic Reverseof cellular respiration

  3. Plants use glucose to: • generate ATP molecules during cellular respiration ( Plants carry out respiration too) • build more complex organic molecules → fats (oils, waxes) → starch → proteins → nucleic acids (DNA and RNA)

  4. Importance of Photosynthesis • food source for other organisms • provides oxygen gas in atmosphere

  5. Site of Photosynthesis: Chloroplast

  6. Why are plants green?

  7. Chloroplast • Grana: stacks of thylakoids that contain chlorophyll ( Light Reaction ) • Stroma: thick fluid that suspends the grana ( Dark Reaction) • Chloroplasts, like mitochondria, have a double membrane

  8. Light WavesLight is composed of photons of energy that travels in wavesThe wavelength of light determines its color.

  9. Electromagnetic Spectrum • ROYGBIV

  10. Plants absorb most wavelengths of light exceptgreen • Green light waves are reflected – which is why plants look green

  11. Photosynthetic Pigments • Chlorophyll is the most abundant (PSP) • chlorophyll a & b absorb red and blue light, reflect green light

  12. Photosynthetic Pigments

  13. Photosynthetic Pigments • having several types of pigments in a leaf allows the plant to absorb more of the light • In this way more energy is available for photosynthesis

  14. Photosynthesis • There are two stages ( Reactions ) • Light reactions: occur in the grana ( Splits H2O and make ATP ) • Dark reactions (Calvin cycle): occur in the stroma (Makes G3P -a precursor to glucose)

  15. Structure of a Chloroplast • The light reactions take place in the thylakoid membrane • The dark reactions take place in the stroma

  16. Stage I - Light Reaction • Also called Light Dependent Reaction • Pigments in the chloroplasts intercept light and begin the light reactions of photosynthesis. • Photosystem: a unit of several hundred chlorophyll a molecules and associated acceptor molecules

  17. Photosystems • when a photon strikes a pigment molecule, the energy jumps from pigment to pigment until it reaches the reaction center

  18. Photosystems

  19. Photosystems • water molecules are split using light energy • This is called photolysis → releases O2 in the atmosphere

  20. Two Types of Photosystems • Photosystems Produce a small amount of ATP and NADPH

  21. Photosynthesis Animations • photosynthesis animation • photosynthesis animation

  22. Stage II: Dark reactions(Calvin Cycle)

  23. Dark Reactions (Calvin Cycle) • Using carbon from CO2 (Low Energy and Inorganic) and the ATP, NADPH, from the light reaction • Calvin cycle synthesizes an energy-rich sugar molecule (glyceraldehyde 3-phosphate or G3P) • G3P is a raw material used to make glucose and other organic molecules

  24. Calvin Cycle

  25. Calvin Cycle • For every 3 CO2 used, 1 G3P is formed • Photosynthesis Fill In Quiz • Respiration & Photosynthesis Quiz

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