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PHOTOSYNTHESIS

Explore the structure and function of chloroplasts in photosynthesis, including the absorption of light, energy conversion, and the role of pigments. Learn about the factors that affect the rate of photosynthesis. This resource is designed for high school biology students at Riverdell High School.

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PHOTOSYNTHESIS

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  1. PHOTOSYNTHESIS BIOLOGY RIVERDELL HIGH SCHOOL Dr. Brandoni

  2. SO FAR…. Themes that keep arising: Structure/function: • proteins, -enzymes, cell membrane fluid-mosaic model, phospholipid chemistry and polarity… Maintaining balance and characteristics of life: -protein shape and temp/acidity, enzyme specificity and homeostasis, osmosis- water regulation , transport… Conservation: of mass, of energy

  3. MOST RECENTLY: Structure/function of cell membrane and its role in transport in order to maintain homeostasis. • Which required energy? • In pairs: Where do our cells get energy from? • What is the energy carrying molecule? • Where is the energy held in its structure? • What do we need to do to get energy? What are “we” called? • Where does our energy ultimately come from? PLANTS- PHOTOSYNTHESIS

  4. WHERE IS THE KITCHEN OF THE PLANT? • CHLOROPLASTS • IN THIS UNIT WE ARE GOING TO LOOK AT THE STRUCTURE/FUNCTION of CHLOROPLASTS IN GENERATING ENERGY AND EXAMINE HOW LIGHT IS CONVERTED TO CHEMICAL ENERGY

  5. MAIN QUESTIONS: Photosynthesis • A. What is photosynthesis? • B. Where does it take place? • C. When does it take place? • D. What happens during photosynthesis?

  6. LAW OF CONSERVATION OF ENERGY: Carbon Cycle DO NOW: • What does the Law of conservation of energy state? • What three things do plants need to stay alive? What do they make from the raw materials? • What are the equations for photosynthesis and respiration? • THINK: Do plant cells undergo cell respiration?

  7. What colored light is MOST useful in photosynthesis? Least?

  8. What colored light is MOST USEFUL? Which is LEAST? MOST USEFUL…. RED and BLUE LEAST USEFUL GREEN!!! HOW CAN THIS BE?????

  9. III. Light and PhotosynthesisA. Nature of Light 1. light is electromagneticradiation a.travels in a vacuum at 186,000miles/sec b. other examples include microwaves, radio waves, X-rays, gamma rays c. each type has a different wavelength and frequency

  10. Nature of Light 2. white light is made of different colors Red OrangeYellowGreenBlue IndigoViolet ---------------------------------------------------------------------- ---------------Decreasing wavelength ---------------------> ---------------Increasing frequency and energy-----------> 3. light that hits an object can be absorbed, transmittedor reflected 4. color of light reflected is color you see a. all colors reflected - color is white b. all colors absorbed - color is black c. all but blue absorbed - color is blue

  11. The Visible Spectrum

  12. WHAT DOES LIGHT PROVIDE? Light in photosynthesis provides energy that will be stored in the bonds of a carbon compound

  13. Bottom Line:Photosynthesis can be divided into 2 phases: • LIGHT REACTIONS: (NEED LIGHT) • Light is converted into chemical energy • H20 breaks to H2 + O (release O2) • H20 is USED • O2 are MADE and ENERGY (ATP) !!!! • CALVIN CYCLE (Dark Reactions): • CO2, isUSED (and energy used) • C6H12O6 is MADE PHOTOSYNTHESIS • 6CO2 + 6H20 ------- C6H12O6 + 6O2

  14. DO AS WE GO QUESTIONS 1. What are the 2 phases of photosynthesis? 2. Where do they occur? ….to answer this, we need to look at the choloroplasts in detail…

  15. Structure of the Chloroplast

  16. WHERE DO THE LIGHT PHASE AND CALVIN CYCLE TAKE PLACE? • LIGHT: Thylakoid • CALVIN CYCLE: Stroma

  17. The Chloroplast

  18. The Chloroplast and Pigments 1. Structure a. grana: stacks of thylakoid membranes PIGMENTS: 1) chlorophyll a: absorbs light in the red range and some in the blue range 2) chlorophyll b: absorbs more in the blue range and assists chlorophyll a

  19. DO…as we go Questions How does light transfer its energy? a. Pigments in chloroplast absorb light 1) light excites electrons Excited electrons transfer energy to high energy compounds

  20. IV. Light Phase - PhotosynthesisA. Chloroplast and Pigments 3) accessory pigments (carotenoids) -yellow, orange, brown pigments that absorb in the green range and sometimes the blue range and pass energy to chlorophyll a THINK: Where do autumn leaves get their colors?

  21. Light Absorption by Pigments in the Chloroplast

  22. Light Waves Absorbed and Reflected by the Leaf

  23. Light Phase of Photosynthesis

  24. C. CAM Pathway 1. Carbon dioxide is fixed in a variety of compounds 2. open stomata at night and close them during the day to conserve water 3. these plants grow slowly 4. examples are cactus and pineapple VI. Alternate Pathways

  25. Cross Section of a Leaf

  26. Stomata Several StomataOpen Closed Showing Guard Cells

  27. Light and Dark Phase Compared

  28. VII. Rate of Photosynthesis A. Depends on 1. light intensity - increases as light intensity increases, then levels off 2. temperature – increases, reaches a high point, then decreases as temperature increases 3. carbon dioxide levels – increases as CO2 levels increase, then levels off

  29. Light Intensity and Rate of Photosynthesis

  30. Temperature and Rate of Photosynthesis

  31. Temperature and Rate of Photosynthesis

  32. CO2 Concentration and Rate of Photosynthesis

  33. Three Factors Affecting Rate of PhotosynthesisLight Intensity CO2 Concentration Temperature

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