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Photosynthesis

Photosynthesis. Photosynthesis. Photosynthesis. Reduction. Oxidation. Oxidation. Reduction. Photosynthesis. How is light energy quantified? Light energy is a form of electromagnetic radiation

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Photosynthesis

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  1. Photosynthesis

  2. Photosynthesis

  3. Photosynthesis Reduction Oxidation Oxidation Reduction

  4. Photosynthesis How is light energy quantified? Light energy is a form of electromagnetic radiation Electromagnetic radiation can be described in terms of a stream of mass-less particles, each traveling in a wave-like pattern and moving at the speed of light. Each mass-less particle contains a certain amount (or bundle) of energy. Each bundle of energy is called a photon, and all electromagnetic radiation consists of these photons. The only difference between the various types of electromagnetic radiation is the amount of energy found in the photons.

  5. Photosynthesis Wavelength is the distance between adjacent peaks in a series of periodic waves

  6. Photosynthesis

  7. Photosynthesis Visible light: 390nm –760nm. nm = nanometers = 10-9 m 390 nm = violets 550 nm = greens 750 nm = reds Which color light has the most energy? Which the least? How do we perceive color & how is it related to the wavelength of light? Why is a plant leaf green?

  8. Photosynthesis

  9. Photosynthesis

  10. Photosynthesis Reflectedlight Light Chloroplast Absorbedlight Transmittedlight

  11. What or how do these molecules convert the energy in the photons to chemical energy? PHOTOSYNTHESIS 6 CO2 + 6 H2O + light energy C6H12O6 + 6 O2 Photosynthesis • Photosynthesis consists of two basic steps • Light dependent reactions – conversion of light energy to chemical energy • Light independent reactions – fixation of carbon dioxide into carbohydrates, utilizing the energy created in the light dependent reactions

  12. Photosynthesis H2O CO2 Chloroplast Light NADP+ ADP+ P LIGHTREACTIONS(in grana) CALVINCYCLE(in stroma) ATP Electrons NADPH O2 Sugar

  13. Photosynthesis

  14. Photosynthesis

  15. Photosynthesis The production of ATP by chemiosmosis in photosynthesis Thylakoidcompartment(high H+) Light Light Thylakoidmembrane Antennamolecules Stroma(low H+) ELECTRON TRANSPORT CHAIN PHOTOSYSTEM II PHOTOSYSTEM I ATP SYNTHASE Figure 7.9

  16. Photosynthesis What happens following the conversion of light energy to ATP & NADPH? The Light independent reactions! Where do these reactions occur? What happens? The Calvin Cycle Carbon dioxide fixed into PGAL 3GP is the precursor molecule to the 6-carbon sugar glucose

  17. Photosynthesis Details of the Calvin cycle INPUT: 3 In a reaction catalyzed by rubisco, 3 molecules of CO2 are fixed. CO2 Step Carbon fixation. 1 1 3 P P 6 P RuBP 3-PGA 6 ATP 3 ADP Step Energy consumption and redox. 2 6 ADP + P CALVINCYCLE 3 ATP 2 6 4 NADPH 6 NADP+ Step Release of one molecule of PGAL. 3 5 P 6 P PGAL PGAL 3 Step Regeneration of RuBP. 4 Glucoseand other compounds OUTPUT: 1 P PGAL

  18. Photosynthesis The Calvin Cycle (aka dark reactions, light independent reactions Begins with the fixation of CO2 to ribulose bisphosphate (5 carbon sugar) with the aid of the enzyme rubisco (ribulose bisphosphate carboxylase) The resulting 6 carbon sugar is split into 2 3-phosphoglycerate molecules (3 carbon sugars) They are reduced & converted to PGAL via the utilization of ATP & NADPH Some of the PGAL is used to make glucose, the rest to regenerate ribulose bisphosphate so that the cycle can fix more carbon dioxide again

  19. Chapter 7 Photosynthesis

  20. Chapter 7 Photosynthesis

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