Photosynthesis Chapter 7

Producer Harvest sun energy Autotroph Photosynthesis Organisms that make their own organic matter Carbohydrates Lipids Proteins Nucleic acid Photosynthesis chloroplast

Who Uses Photosynthesis

Who Uses Photosynthesis Some protozoa

Who Uses Photosynthesis Some Bacteria like cyanobacteria

Photosynthesis Harvest of light energy from sun and convert to glucose Uses co2 & water Produces glucose & oxygen Occurs in the chloroplast Uses pigments (Chlorophyll a & b) Metabolic pathway (Reduction Oxidation) Light phase Dark phase (calvin cycle)

Photosynthesic Structures Green parts of plants (or animals) contain chloroplasts Concentrated in leaves ½ million/ Sq mm Chlorophyll (a&b) Green pigment Stomata used to regulate gas availability

Stomata Regulate Gas exchange= co2, o2, water vapor Reduce water evaporation 6Co2 + 6H2O C6H12O6 +6O2

Chloroplast Membrane bound organelle Stroma- space Granum of stacked thylakoids Site of photosynthesis Interconnected membrane sacs Stroma Granum

Light Light interacts with matter Electromagnetic energy (radiation) Aka visible light Contains energy Light interacts with matter Reflected visible Transmitted Visible Absorbed Pigments Energy form changes

Why are Plants are green? Absorb red, orange, blue, green Reflect or transmit green

Photosynthetic pigments Chlorophyll a Blue-green Absorbs Violet-blue & red light Chlorophyll b Yellow-green Accessory pigment Absorbs Violet-blue & red-orange light Carotinoids Yellow-orange Absorb violet & blue-green Broaden absorption Photoprotection communication

Photosynthesis How Does It Do That???

Photosynthesis Light reactions Dark reactions Require light Convert solar energy to chemical energy Dark reactions Synthesis Produces sugar

Light stage Converts light energy into chemical energy Chlorophyll absorbs light Use light energy to split water H is taken from H2O Produce oxygen gas as waste Energy harvesting stage Cycles ADP to ATP Cycles NADP+ to NADPH Energy Harvesting

Electron from water travels down the electron transport chain Creates H+ gradient Chemiosmosis

So Far we have ATP & NADPH But doesn’t photosynthesis make sugar?? Where’s the Sugar?

Dark Reactions Aka calvin cycle Light independent No direct investment of light required Series of reactions that assemble glucose Use co2 & energy sources (nadph, atp) from light reactions

Cellular Respiration vs Photosynthesis H from sugar to o to make water exergonic Electron transport chain harvests E Photosynthesis H from h2o to co2= sugar Endogonic Uses light energy to drive Electron transport chain harvests