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Photosynthesis

Photosynthesis. Energy & Life. Overview of Photosynthesis. Autotrophs. Plants and some other types of organisms that contain chlorophyll are able to use light energy from the sun to produce food. Autotrophs. Autotrophs include organisms that make their own food

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Photosynthesis

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  1. Photosynthesis Energy & Life

  2. Overview of Photosynthesis

  3. Autotrophs Plants and some other types of organisms that contain chlorophyll are able to use light energy from the sun to produce food.

  4. Autotrophs • Autotrophs include organismsthat make their own food • Autotrophs can use the sun’s energy directly Euglena

  5. Heterotrophs • Heterotrophs are organisms that can NOT make their own food • Heterotrophs can NOT directly use the sun’s energy

  6. Energy • Energy can be changed from one form to another • Energy can be stored in chemical bonds & then released later Candles release energy as HEAT & LIGHT

  7. ATP – Cellular Energy • Adenosine Triphosphate • Contains two, high-energy phosphate bonds • Also contains the nitrogen base adenine & a ribose sugar

  8. ADP • Adenosine Diphosphate • ATP releases energy, a free phosphate, & ADP when cells take energy from ATP One phosphate bond has been removed

  9. Importance of ATP Principal Compound Used To Store Energy In Living Organisms. Most energy stored between the last 2 phosphate bonds

  10. Releasing Energy From ATP • ATP is constantly being used and remade by cells • ATP provides all of the energy for cell activities • The high energy phosphate bonds can be BROKEN to release energy

  11. Releasing Energy From ATP • Adding A Phosphate Group To ADP stores Energy in ATP • Removing A Phosphate Group From ATP Releases Energy & forms ADP Loose Gain

  12. Cells Using Biochemical Energy Cells Use ATP For: • Active transport • Movement • Photosynthesis • Protein Synthesis • Cellular respiration • All other cellular reactions

  13. Glucose • Glucose is a monosaccharide • C6H12O6 • One Molecule of glucose Stores 90 Times More Chemical Energy Than One Molecule of ATP

  14. History of Photosynthesis & Plant Pigments

  15. Photosynthesis • Involves the Use Of light Energy to convert Water (H20) and Carbon Dioxide (CO2) into Oxygen (O2) and High Energy Carbohydrates (sugars, e.g. Glucose) & Starches

  16. Investigating Photosynthesis • Early Research Focused On The Overall Process • Later Researchers Investigated The Detailed Chemical Pathways • Many Scientists Have Contributed To Understanding Photosynthesis

  17. Early Questions on Plants Several Centuries Ago, The Question Was:Does the increase in mass of a plant come from the air? The soil? The Water?

  18. Van Helmont’s Experiment 1643 • Planted a seed into A pre-measured amount of soil and watered for 5 years • Weighed Plant & Soil. Plant Was 75 kg, Soil The Same. • Concluded Mass Came From Water

  19. A candle requires oxygen to burn. Can you think of an experimental design that would prove plants make oxygen?

  20. Priestley’s Experiment 1771 • Burned Candle In Bell Jar Until It Went Out. • Placed Sprig Of Mint In Bell Jar For A Few Days. • Candle Could Be Relit And Burn. • Concluded Plants Released Substance (O2) Necessary For burning.

  21. 1779 Repeated Priestly experiment with & without sunlight

  22. Results of Ingenhousz’s Experiment • Showed That Priestley’s Results Only Occurred In The Presence Of Sunlight. • Light Was Necessary For Plants To Produce The “Burning Gas” or oxygen

  23. Melvin Calvin 1948 • First to trace the path that carbon (CO2) takes in forming Glucose • Does NOT require sunlight • Called the Calvin Cycle or Light Independent Reaction • Also knownas the Dark Reaction

  24. Rudolph Marcus 1992 • Studied the Light Independent Reactions • First to describe the Electron transport Chain

  25. The Photosynthesis Equation

  26. Pigments • In addition to water, carbon dioxide, and light energy, photosynthesis requires Pigments • Chlorophyll is the primary light-absorbing pigment in autotrophs • Chlorophyll is found inside chloroplasts

  27. Light and Pigments • Energy From The Sun Enters Earth’s Biosphere As Photons • Photon = Light Energy Unit • Light Contains A Mixture Of Wavelengths • Different Wavelengths Have Different Colors

  28. The Biochemical Reactions

  29. It Begins with Sunlight!

  30. Photoautotrophs Absorb Light Energy

  31. Inside A Chloroplast

  32. Structure of the Chloroplast • Double membrane organelle • Outer membrane smooth • Inner membrane forms stacks of connected sacs called thylakoids • Thylakoid stack is called the granun (grana-plural) • Gel-like material around grana called stroma

  33. Thylakoid membranes • Light Dependent reactions occur here

  34. Photosynthesis Overview

  35. Light Dependent Reactions • Occurs across the thylakoid membranes • Uses light energy • Produce Oxygen from water • Convert ADP to ATP

  36. Light Dependent Reaction

  37. Light Dependent Reaction

  38. Oh it could get a whole lot more complicated folks!

  39. Light Reaction Summary Reactants: • H2O • Light Energy Energy Products: • ATP • NADPH

  40. The Calvin Cycle

  41. Factors Affecting the Rate of Photosynthesis • Amount of available water • Temperature • Amount of available light energy

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