factors affecting rate of photosynthesis

• what is a limiting factor

  a factor which prevents photosynthesis from happening any faster
• what are the 3 limiting factors

  • temperature
  • light intensity
  • co2 concentration
• what is the limiting factor at winter

  low temperature
• what is the limiting factor at night

  light intensity
• what else can affect the rate of photosynthesis

  n.o chloroplasts/ amount of chlorophyll
• how does temp affect the rate of photosynthesis

  • as temp increases, rate of photosynthesis increases due to there being alot of co2 + light and there is more kinetic energy between the particles
  • meaning there arer more collisions between enzymes+substrates
• what happens at high temps

  at high temps (over 45C) enzymes begin to denature, dereasing the rate of photosynthesis
• what else happens as the temp increases the kinetic energy between the particles

  it also increases the speed at which co2 and water move through plant
• graph for temperature


  a curve
• how does light intensity affect the rate of photosynthesis

  • as light intensity increases, rate of photosynthesis increases as there is alot of co2+a suitable temp
  • but only until a certain point where another factor (eg co2 conc/ temp) becomes the limiting factor
  • this is because it is in short supply+causes graph to plateu
• why has another factor become the limiting factor

  as that factor is in short supply, causing graph to plateu
• what is another reason for another factor being the limiting factor

  as rate has reached it's maximum
• how does co2 concentration affect rate of photosynthesis

  • as co2 conc increases, rate of photosynthesis increases as there is alot of light+suitable temp
  • hwoever, only till a certain point as another factor (eg: temp/light intensity) has now become the limiting factor
  • this prevents rate of photosynthesis from increasing as it's in short supply, causing graph to plateu
• how can the n.o chloroplasts affect rate of photosynthesis

  • more chloroplasts = more chlorophyll (used to absorb light for photosynthesis) = faster rate of photosynthesis
• what can the amount of chlorophyll be affected by

  • diseases (tobacco mosaic virus)
  • lack of nutrients (eg: magnesium)
  • loss of leaves (less leaves = less chloroplasts = less chlorophyll)