limiting factors

• what is a limiting factor in terms of photosynthesis?

  factor present at the lowest/least favourable amount, limiting the process of photosynthesis
• what are the three main limiting factors of photosynthesis?

  • carbon dioxide- more increases the rate of carbon fixation
  • temperature- has to be optimal for the enzymes to work at faster rates
  • light intensity- increases rate of ATP and reduced NADP production
• what is a compensation point?

  no net movement of gases into or out of a plant
• how does light intensity relate to the stomata?

  • regulates stomatal opening/closure
  • more light intensity means stomata open
• what is the effect of temperature on the Calvin cycle?

  • lower temperatures- enzymes and substrate molecules have less kinetic energy
  • fewer successful collisions
  • lower reaction rate
  • therefore lower concentrations of TP, GP and RuBP
• how does the carbon dioxide concentration have an affect on the Calvin cycle?

  • if there's little carbon dioxide, this decreases the rate of carbon fixation
  • therefore leading to reduced concentrations of GP
  • therefore the rate of TP production decreases
  • The concentration of RuBP will increase as it is still being formed from TP but not being fixed to carbon dioxide, so it accumulates
• what happens to stomata in times of water stress?

  they close
• how does light intensity affect the Calvin cycle?

  • reduces the rate of the light dependent stage
  • reduces the quantity of ATP and reduced NADP produced
  • ATP and NADP are needed to convert GP and TP
  • GP will accumulate and concentration will increase, and the concentration of TP will decrease
  • less TP to regenerate RuBP, so concentration of RuBP decreases
• how does light intensity affect the Calvin cycle?


  • reduces the rate of the light dependent stage
  • reduces the quantity of ATP and reduced NADP produced
  • ATP and NADP are needed to convert GP and TP
  • GP will accumulate and concentration will increase, and the concentration of TP will decrease
  • less TP to regenerate RuBP, so concentration of RuBP decreases