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Photosynthesis

Explore the process of photosynthesis, its importance in energy production, and the adaptations plants have developed to optimize this process. Learn about the difference between C3 and C4 plants through a Venn diagram comparison.

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Photosynthesis

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  1. Photosynthesis

  2. PHOTOSYNTHESIS

  3. SUN photons glucose Photosynthesis • Carbon dioxide (CO2) requiring process that uses light energy (photons) and water (H2O) to produce organic macromolecules (glucose). 6CO2 + 6H2O  C6H12O6 + 6O2

  4. Question: Where does photosynthesis take place?

  5. Chloroplast Mesophyll Cell Stoma Plants • Autotrophs – produce their own food (glucose) • Process called photosynthesis • Mainly occurs in the leaves: a. stoma - pores b. mesophyll cells

  6. Oxygen (O2) Carbon Dioxide (CO2) Guard Cell Guard Cell Stomata (stoma) Pores in a plant’s cuticle through which water vapor and gases(CO2 & O2) are exchanged between the plant and the atmosphere. Stoma Found on the underside of leaves

  7. Nucleus Cell Wall Chloroplast Central Vacuole Mesophyll Cell of Leaf Photosynthesis occurs in these cells!

  8. Stroma Outer Membrane Thylakoid Granum Inner Membrane Chloroplast Organelle where photosynthesistakes place. Thylakoid stacks are connected together

  9. Thylakoid Membrane Thylakoid Space Granum Thylakoid Grana make up the inner membrane

  10. Light Dependent Reactions

  11. Question: Why are plants green?

  12. Chlorophyll Molecules • Located in the thylakoid membranes] • Chlorophyll pigments harvest energy (photons) by absorbing certain • wavelengths (blue-420 nm and red-660 nm are most important) • Plants are green because the green wavelength is reflected, not absorbed.

  13. Amazing Chloroplast

  14. 400 500 600 700 Short wave Long wave (more energy) (less energy) Wavelength of Light (nm)

  15. violetbluegreenyelloworangered Absorption of Light by Chlorophyll Chlorophyll absorbs blue-violet & red light best Absorption wavelength

  16. Question: During the fall, what causes the leaves to change colors?

  17. Fall Colors • In addition to the chlorophyll pigments, there are other pigments present • During the fall, the green chlorophyll pigments are greatly reduced revealing the other pigments • Carotenoids are pigments that are either red, orange, or yellow

  18. Question: What do cells use for energy?

  19. How do cells obtain energy?

  20. Energy for Life on Earth • Sunlight is the ULTIMATE energy for all life on Earth • Plants store energy in the chemical bonds of sugars • Chemical energy is released as ATP during cellular respiration

  21. Structure of ATP • ATP stands for adenosine triphosphate • It is composed of the nitrogen base ADENINE, the pentose (5C) sugar RIBOSE, and three PHOSPHATE groups • The LAST phosphate group is bonded with a HIGH ENERGY chemical bond • This bond can be BROKEN to release ENERGY for CELLS to use

  22. Removing a Phosphate from ATP Breaking the LAST PHOSPHATE bond from ATP, will --- • Release ENERGY for cells to use • Form ADP • Produce a FREE PHOSPHATE GROUP

  23. High Energy Phosphate Bond

  24. FREE PHOSPHATE can be re-attached to ADP reforming ATP Process called Phosphorylation

  25. Parts of Photosynthesis

  26. Types of Photosynthesis

  27. Two Parts of Photosynthesis Two reactions make up photosynthesis: 1.Light Reaction or Light Dependent Reaction - Produces energy from solar power (photons) in the form of ATP and NADPH. SUN

  28. Two Parts of Photosynthesis 2. Calvin Cycle or Light Independent Reaction • Uses energy (ATP and NADPH) from light reaction to make sugar (glucose).

  29. Light Reaction (Electron Flow) • Occurs in the Thylakoid membranes

  30. Calvin Cycle • Carbon Fixation (light independent reaction) • C3 plants (80% of plants on earth) • Occurs in the stroma • Uses ATP and NADPH from light reaction as energy • Uses CO2 • To produce glucose: it takes 6 turns and uses 18 ATP and 12 NADPH.

  31. STROMA– where Calvin Cycle occurs Outer Membrane Thylakoid Granum Inner Membrane Chloroplast

  32. C3 Glucose Calvin Cycle Remember: C3 = Calvin Cycle

  33. Photorespiration • Occurs on hot, dry, bright days Stomates close • Fixation of O2 instead of CO2 • Produces 2-C molecules instead of 3-C sugar molecules • Produces no sugar molecules or no ATP

  34. Photorespiration Because of photorespiration, plants have special adaptations to limit the effect of photorespiration: 1. C4 plants 2. CAM plants

  35. C4 Plants • Hot, moist environments • 15% of plants (grasses, corn, sugarcane)

  36. CAM Plants • Hot, dry environments • 5% of plants (cactus and ice plants) • Stomates closed during day • Stomates open during the night • Light reaction - occurs during the day • Calvin Cycle - occurs when CO2 is present

  37. Question: Why do CAM plants close their stomata during the day?

  38. Cam plants close their stomata in the hottest part of the day to conserve water

  39. What is the Difference ? • Journal in your notebooks using a Venn diagram to discuss your comparisons between C3 and C4 Plants.

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