MODULE 2.2 Light

• The photosynthesis equation is true for all 3 types of adaptations (C3, C4, & CAM)
• The result of the photosynthesis equation stays the same
• Improvements on the efficiency

  Due to temperature effect on the protein RUBISCO in the Calvin Cycle
• Light Dependent stage of photosynthesis

  Electron Transport Chain
• Light Independent stage of photosynthesis

  The Calvin Cycle
• Photolysis


  Light dependent stage
• The Calvin Cycle


  Light independent stage
• RubisCO


  An enzyme found in plant chloroplast that fixes CO2
• RubisCO is probably the earth's most abundant protein
• RubisCO is temperature sensitive


  Yield of C3 plants decline with increased temperatures
• RubisCO uptake of O2

  When the stomata are closed during higher temperatures
• Inefficiencies due to RubisCO


  • Temperature
  • Photorespiration
• Photosynthesis types

  • C3
  • C4
  • CAM
• C3 plants


  • No special modifications
• C4 plants


  • Hot weather plants
  • Separate fixation
• CAM plants

  • Desert plants
  • Separate fixation day/night
• C3 plants make up 85% of plant species
• C4 plants make up 5% of plant species
• CAM plants make up 10% of plant species
• Some water plants have also adapted to being CAM photosynthesizing
• Light saturation and photo bleaching can occur when leaves are not adapted to intense direct light
• Xyanthophyll production helps with sun flickers for under canopy species
• Global food shortage of C3 plants as yield decreases due to increase in global temperatures
• The C4 Rice project funded by the Bill & Malinda Gates foundation aims to change Rice, a C3 plant, into C4 to make it more efficient and increase yield in higher temperatures