Photosynthesis

• Photoautotrophs make their own food from CO2 and H2O using light energy from the sun.
• The main light-trapping pigments are chlorophylls
• There are two types of chlorophylls: Chlorophyll A and Chlorophyll B
• Chlorophylls are found in the chloroplasts
• Accessory pigments assist in trapping light energy
• Chlorophylls absorb all colours and reflect green
• • Plants, cyanobacteria, algae, and some other protists contain chlorophyll to trap light energy for photosynthesis
• Chloroplasts have a double membrane
• Chloroplasts are found in plant cells
• Chloroplasts have internal structures that are held within a green jelly like liquid called stroma
• Thylakoids (fluid-filled sacs) are stacked up in the chloroplast into structures called grana which are linked together by membrane called lamellae
• Photosynthesis Equations

  Light energy

  Carbon dioxide + water --> glucose + oxygen +water

  Chlorophyll

   

  Light energy

   6CO2 + 12H2O → C6H12O6 + 6O2 + 6H2O

  Chlorophyll
• Light dependent reactions: Light energy is absorbed by chlorophyll and used to make ATP
• Light dependent reactions must use light and occur within the thylakoids
• Hydrolysis: splitting of water into H+ ions and oxygen. The oxygen is either used by the plant or released into the atmosphere
• Light dependent reactions must occur first
• Light independent reactions are used to add phosphate group to ADP to form ATP, and to form NADPH (reduced NADP). ATP transfers energy and NADP transfers hydrogen to the light-independent reaction
• Light independent reactions occurs in the stroma