Photosynthesis

• Photosynthesis


  Process that uses energy to change carbon dioxide and water into glucose and oxygen
• Photosynthesis


  1. Occurs in chloroplasts in green plant cells

  2. Chloroplasts contain pigments like chlorophyll that absorb light

  3. Energy is transferred to the chloroplasts from the environment by light
• Endothermic


  Photosynthesis is a process where energy is transferred from the environment
• Photosynthesis


  1. Carbon dioxide + water

  2. Glucose + oxygen
• Ways plants use glucose


  • Respiration
  • Making cellulose
  • Making amino acids
  • Stored as oils or fats
  • Stored as starch
• Starch


  Insoluble, better for storing than glucose
• Factors affecting rate of photosynthesis


  • Light intensity
  • Concentration of CO2
  • Temperature
• Plants also need water for photosynthesis, but when water is the limiting factor, the plant is already in trouble
• Limiting factor


  Factor that is stopping photosynthesis from happening any faster
• As light intensity increases


  Rate of photosynthesis increases, up to a point
• As CO2 concentration increases


  Rate of photosynthesis increases, up to a point
• Temperature


  Affects the rate of photosynthesis because it affects the enzymes involved
• Enzymes are damaged at temperatures above 45°C
• Measuring rate of photosynthesis


  1. Use Canadian pondweed

  2. Measure oxygen production

  3. Vary light intensity, temperature or CO2 concentration
• Inverse square law


  As distance from light source increases, light intensity decreases proportionally to the square of the distance
• Greenhouses


  • Trap heat
  • Provide artificial light
  • Increase CO2 levels
  • Protect from pests and diseases
  • Allow addition of fertilizers
• Greenhouses allow farmers to create ideal conditions for photosynthesis, leading to faster plant growth and more frequent harvests