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Photosynthesis

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  1. Photosynthesis

  2. Autotroph vs. Heterotroph • Autotroph- organism that makes its own food • We call autotrophsProducers • Plants, algae • Heterotroph- an organism that cannot make its own food • Obtain energy by eating other organisms • We call heterotrophsConsumers • Animals, most bacteria, fungi

  3. THE BASICS OF PHOTOSYNTHESIS • Almost all plants are photosynthetic autotrophs, as are some bacteria and protists • Autotrophs generate their own organic matter through photosynthesis • Sunlight energy is transformed to energy stored in the form of chemical bonds (c) Euglena (d) Cyanobacteria (b) Kelp (a) Mosses, ferns, and flowering plants

  4. Photosynthesis • Photosynthesis occurs in all cells with chloroplasts (mainly plants) • Step 1: photo- • Light energy is harvested • Step 2: -synthesis • Sugar is made

  5. AN OVERVIEW OF PHOTOSYNTHESIS • Photosynthesis is the process by which autotrophic organisms use light energy to make sugar and oxygen gas from carbon dioxide and water Carbondioxide Water Glucose Oxygengas PHOTOSYNTHESIS Glucose = sugar or carbohydrate

  6. What’s with Light???

  7. THE SUN: MAIN SOURCE OF ENERGY FOR LIFE ON EARTH

  8. Electromagnetic Spectrum and Visible Light Gammarays Infrared & Microwaves X-rays UV Radio waves Visible light Wavelength (nm)

  9. WHY ARE PLANTS GREEN? Different wavelengths of visible light are seen by the human eye as different colors. Gammarays Micro-waves Radio waves X-rays UV Infrared Visible light Wavelength (nm)

  10. Why are plants green? Reflected light Transmitted light

  11. The feathers of male cardinals are loaded with carotenoid pigments. These pigments absorb some wavelengths of light and reflect others. Reflected light Sunlight minus absorbed wavelengths or colors equals the apparent color of an object.

  12. THE COLOR OF LIGHT SEEN IS THE COLOR NOT ABSORBED • Chloroplasts absorb light energy and convert it to chemical energy Reflected light Light Absorbed light Transmitted light Chloroplast

  13. Question: Where does photosynthesis take place? 13

  14. Chloroplast LEAF CROSS SECTION MESOPHYLL CELL • In the chloroplasts!! LEAF Mesophyll Intermembrane space CHLOROPLAST Outer membrane Granum Innermembrane Grana Stroma Thylakoidcompartment Stroma Thylakoid

  15. Chloroplasts are comprised of: • outer membrane and inner membrane (together form the chloroplast envelope) • stroma (a thick fluid) • thylakoids (called grana when in stacks) • The pigement chlorophyll is imbedded in the thylakoidmemebrane Notice that the Thylakoidstacks are connected together

  16. Where Photosynthesis happens • Pigment molecules called chlorophyll are on the surface of the thylakoid membrane • Chlorophyll gives plants their green color • Chlorophyll molecules absorb and capture light energy from the sun • The chlorophyll then uses the energy to combine H, C, and O atoms into sugars and oxygen molecules • Nearly all of the Oxygen in our atmosphere has been produced by plants

  17. In Summary… Photosynthesis • Chloroplasts convert light energy into chemical energy Carbon Dioxide + Water + Light  Sugar + Oxygen 6 CO2 + 6 H2O + light energy C 6H12O6 + 6 O2

  18. pigmentsin the chloroplast- not just chlorophyll • Chlorophyll a: most common pigment in chloroplast (absorbs blue &red light and reflects green light thus giving the chloroplast a green color)(chloro = green phylla + leaf) • Accessory pigments: additional pigments that absorb different wavelengths (carotene, chlorophyll b, & xanthophyll)

  19. But it’s not that easy…Photosynthesis occurs in two different phases

  20. The Light Phase • This phase occurs in thethylakoid • In this phase, light is captured by the chlorophyll molecules • The chlorophyll molecules use the energy from the light to make: • ATP (cellular energy molecule) • NADPH (another high energy molecule) • Both of these molecules move on to the dark phase

  21. “Waste” Products • Water is split, and Oxygen created during the light phase • Oxygen is released, hydrogen molecules from the water used in dark phase • Remember, this is the Oxygen that you breathe

  22. The complicated view…(not on test)

  23. 2. H2O 3. CO2 1. light 4. stroma 7. NADP+ 8.ADP+P_ 11. Calvin Cycle 6. light reaction 5. granum 9.ATP 12. thylakoid 10.NADPH 13. O2 14. sugar The simplified version (on test) Light Reactions

  24. The Calvin Cycle • Also known as the Light Independent or Carbon fixation phase • This set of reaction does not rely on light • Occurs in the stroma (fluid inside of chloroplast)

  25. The calvin cycle uses the H from the H20 and the C from the CO2 • It also utilizes the ATP and the NADPH from the Light Reactions • With these components, sugars are made in the stroma

  26. 2. H2O 3. CO2 1. light 4. stroma 7. NADP+ 8.ADP+P_ 11. Calvin Cycle 6. light reaction 5. granum 9.ATP 12. thylakoid 10.NADPH 14. sugar 13. O2 Calvin Cycle

  27. What is the Purpose? • Sugar is produced during this phase • Sugar can be used to synthesize more complex molecules like: • Starch • Fats/Lipids • Sugar can be used to make ATP during cell Respiration • It can be stored in the tissues of organisms

  28. light energy  6CO2 + 6H2O + + 6O2 C6H12O6 So what does a plant need? • Bring In • light • CO2 • H2O • Let Out • O2 • Produce • sugars leaves shoot roots

  29. Factors Affecting Rate of Photosynthesis • Temperature: increases rate up to a certain point • Light Intensity: increases rate up to a certain point • CO2 level: Increases rate up to a certain point • Water: decrease water, decrease photosynthesis • Minerals; Ex. Magnesium, Nitrogen

  30. Photosynthesis Summary • Who? • Green plants, algae, autotrophs • Materials: • CO2 + Water + Light • Energy Source: • Light + Sunlight • Products: • Food + Oxygen • Timing: • When light is present • Location: • chloroplast