photosynthesis - converts radiant energy to chemical energy

• 6CO2 + 12H2O >> C6H12O6 + 6O2 + 6H2O
• dependent on light and chlorophyll
• oxygen released into environment; sugar used for growth or storage
• reactant/product water molecules are different
• chloroplast - organelle for photosynthesis
  • thylakoids - photosynthetic membranes
  • grana - stacks of thylakoids
  • lamellae - holds grana in place
  • stroma - semiliquid in chloroplasts
• photochemical (light) reactions -
  • splits water to release O2, electrons, protons
  • almost at instantaneous speed
  • light-dependent
• biochemical (dark) reactions (Calvin cycle) -
  • converts CO2 to sugar
  • fast, but slower than photochemical reaction
  • light-independent

paper chromatography - separates dissolved compounds

• pigment - substance that absorbs light
  • primary photosynthetic pigments - chlorphyll a/b
  • accessory pigments - also absorb light; ex. carotene, xanthophyll
• different mov't of pigments on paper due to solubility and tendencies to stick
• pigments strongly absorbed move slowly
• pigments weakly absorbed move faster
• Rf = distance moved by pigment / distance from pigment origin to solvent front

spectroscope - instrument that separates white light into component colors

• placing chlorophyll between light/spectroscope blocks out light absorbed by chlorophyll

fluorescence - release of light energy

• light only produces reactions when absorbed by a molecule
• chlorophyll appears green because it absorbs all other light wavelengths
• light excites the electrons, bossting them to a higher energy level