Photosynthesis Photosynthesis • An anabolic, endergonic, carbon dioxide anabolic, endergonic, carbon dioxide (CO (CO 2 ) ) requiring process that uses light light energy (photons) energy (photons) and water (H water (H 2 O) O) to produce organic macromolecules organic macromolecules (glucose). (glucose). 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 glucose glucose SUN photons photons • Where does photosynthesis take plac Where does photosynthesis take plac
SUN. photons. glucose. Photosynthesis. An anabolic, endergonic, carbon dioxide (CO 2 ) requiring process that uses light energy (photons) and water (H 2 O) to produce organic macromolecules (glucose). 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2. - PowerPoint PPT Presentation
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PhotosynthesisPhotosynthesis
• An anabolic, endergonic, carbon dioxide anabolic, endergonic, carbon dioxide (CO(CO22)) requiring process that uses light light energy (photons)energy (photons) and water (Hwater (H22O)O) to produce organic macromolecules organic macromolecules (glucose).(glucose).
6CO2 + 6H2O C6H12O6 + 6O2 glucoseglucose
SUN
photonsphotons
•Where does photosynthesis take place?Where does photosynthesis take place?
• PoresPores in a plant’s cuticle through which waterwater and gasesgases are exchanged between the plant and the atmosphere.
Guard Cell
Guard Cell
Carbon Dioxide (CO2)
Oxygen (O2)
Water (H2O)
Mesophyll Mesophyll CellCell
Cell WallNucleus
Chloroplast
Central Vacuole
ChloroplastChloroplast• OrganelleOrganelle where photosynthesisphotosynthesis takes
place.
GranumThylakoid
Stroma
Outer Membrane
Inner Membrane
ThylakoidThylakoid
Thylakoid Membrane
Thylakoid SpaceGranum
•Why are plants green?Why are plants green?
Chlorophyll MoleculesChlorophyll Molecules• Located in the thylakoid thylakoid
membranesmembranes.
• Chlorophyll have MgMg++ in the center.
• Chlorophyll pigmentsChlorophyll pigments harvest energy (photons) by absorbingabsorbing certain wavelengthswavelengths (blue-420 blue-420 nmnm and red-660 nm are most important).
• PlantsPlants are greengreen because the green wavelengthwavelength is
reflectedreflected, not absorbednot absorbed.
Wavelength of Light Wavelength of Light (nm)(nm)
400 500 600 700
Short wave Long wave(more energy) (less energy)
Absorption of Chlorophyll
wavelengthwavelength
Absorption
violet blue green yellow orange red
•During the fall, what causes the leaves to change colors?During the fall, what causes the leaves to change colors?
• Occurs in the thylakoid membranethylakoid membrane.• Uses Photosystem I onlyPhotosystem I only• P700 reaction center- chlorophyll a • Uses Electron Transport Chain Electron Transport Chain
• Because of photorespirationBecause of photorespiration: PlantsPlants have special adaptationsspecial adaptations to limit the effect of photorespirationphotorespiration.
1.1. C4 plantsC4 plants
2.2. CAM plantsCAM plants
C4 PlantsC4 Plants
• Hot, moist environmentsHot, moist environments.
• 15% of plants (grasses, corn, 15% of plants (grasses, corn, sugarcane).sugarcane).