3.3 photosynthesis

• what is photosynthesis?


  a series of chemical reactions, traps energy from the sun and converts it to food
• where does photosynthesis occur?

  chloroplasts in green plant cells
• photosynthesis word equation

  carbon dioxide + water (with light + @chlorophyll) → glucose + oxygen
• chlorophyll


  the green in plants, responsible for absorbing sunlight
• photosynthesis equation

  CO2 + H2O (with light + @chlorophyll) → C6H12O6 + O2
• how many stages in photosynthesis?

  2, light reaction + carbon fixation
• stage 1: light reaction


  light energy goes to chlorophyll which separates water to hydrogen (used in stage 2) and oxygen which goes into the air, light also goes through a chemical reaction and becomes ATP (used in stage 2)
• stage 2: carbon fixation


  hydrogen and carbon dioxide goes through a series of enzyme controlled reactions powered by ATP to form sugar
• glucose


  sugar made by photosynthesis
• factors that affect rate of respiration

  light intensity, carbon dioxide concentration, temperature
• what do plants use sugar for?

  respiration, making cellulose (structural), stored as starch (storage)
• algal balls

  indicator of light intensity and carbon dioxide
• products of photosynthesis


  oxygen will relight a glowing splint, hydrogen will burn with a squeaky pop, starch will turn a lead black/blue when iodine solution is added