Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Photosynthesis What is the ultimate source of all energy How does the energy get from the sun into the foods we eat? Why do we see colors? The sun sends downs little packets of light energy called: PHOTONS Why do we see colors? Photons group together in waves The waves have different lengths Each “wavelength” presents itself as a color Photons Wavelengths Why do we see colors? Plants reflect this color of light. That’s why most plants are GREEN Plant pigments like chlorophyll absorb these colors of light so these colors are not seen. What colors of light would a plant with purple leaves absorb? What colors are being absorbed and what colors are being reflected? Photos courtesy of flowerpictures.net and picturesof.net Why do we see colors? What do we call the compounds that absorb and reflect wavelengths of light? Which compound reflects the green wavelengths thereby making plants green? Where would we find this compound? Chloroplast structure Disks called GRANA contain the pigment CHLOROPHYLL. The liquid portion of a chloroplast is the STROMA Where do we find chloroplasts? Chloroplasts are found in cells of leaves. Chloroplast containing chlorophyll stoma Review 1. 2. 3. 4. 5. What is the ultimate source of all energy? In what form does light energy come to the earth? What compounds absorbs wavelengths? How do we see colors? Where in a leaf do we find pigments? What process captures the light energy and uses it to make food? OVERVIEW OF PHOTOSYNTHESIS SUNLIGHT PROVIDES THE ENERGY FOR PHOTOSYNTHESIS PLANTS MAKE GLUCOSE AND OXYGEN PLANTS TAKE IN CO2 AND H2O Photosynthesis What is photosynthesis? Photosynthesis is the process by which: light TAKE IN AND USING water carbon dioxide PLANTS (producers) chlorophyll MAKE oxygen glucose Photosynthesis 2 steps: Light reactions Dark reactions (aka Calvin cycle) Light Reaction Dark Reaction Who was Calvin anyway? A member of the faculty at UC Berkeley since 1937, Melvin Calvin received the 1961 Nobel prize in chemistry for identifying the path of carbon in photosynthesis. The cycle of reactions in the dark phase of photosynthesis was named after him for his work in identifying the processes taking place. Photosynthesis Light reaction: Occurs in the grana Must have light light LIGHT Light REACTION Reaction grana (chlorophyll) Dark Reaction Photosynthesis Dark reactions (aka Calvin cycle): Occurs in the stroma Occurs in the light and dark Light Reaction DARK Dark REACTION Reaction stroma (liquid) Step 1: Light Reactions O2isiskept light water H energy released is split for the by reacts the dark light reaction with energy the chlorophyll O2 O2 O2 O H2O O2 O2 H H H2 How does the O2 leave the leaf? Step 2: Dark Reactions AKA: CALVIN CYCLE glucose H CO the from enters the is the water theHproduct and splitCO in2 2reactants the light reaction is chloroplast combine present COdoes 2 How CO2 CO enter 2 the plant? CO2 H H CO2 H + CO2 C6H12O6 Other carbohydrates besides glucose may be made in photosynthesis Photosynthesis Review Light reactions: H2O split into H2 + O Dark reactions: H + CO2 = C6H12O6 H2O Light Reaction chlorophyll Dark Reaction C6H12O6 Photosynthesis Formula How would this be written as a chemical equation? What goes in? (the reactants) What comes out? (the products) H2O H2O CO2 Light Reaction chlorophyll C6H12O6 O2 Dark Reaction C6H12O6 Photosynthesis Formula What’s wrong with this equation? The number of atoms is not equal on both sides of the equation. one carbon atom reactant 6 H2O 6 CO2 6 carbon atoms product (1) C6H12O6 6 O2 Balance the equation so that the number of atoms of each element is equal on both sides. Now balance it as if TWO glucose molecules were being produced. Photosynthesis Review What goes in? (the reactants) What comes out? (the products) light 6CO2 + 6H2O H2O chlorophyll Light Reaction chlorophyll 6O2 + C6H12O6 Dark Reaction C6H12O6