factors that affect photosynthesis

• 3 environmental factors that affect the rate of photosynthesis

  • temperature
  • light intensity
  • carbon dioxide concentration
• with references to photosynthesis, what is a limiting factor

  a limiting factor is anything that constrains (limits) the rate of reaction
• describe and explain how the rate of photosynthesis varies with temperature

  • the rate initially increases with temperature because the particles have more energy and move faster, so they react more frequently
  • the highest rate occurs at the optimum temperature for the enzymes
  • at higher temperatures, the rate decreases as bonds holding the enzymes together begin to break, so the enzymes change shape, meaning they're no longer as complementary to the substrates
  • the rate falls to 0 as the enzymes denature
• why do farmers use greenhouses

  • greenhouses help trap the heat energy from sunlight, and do increases the temperature
  • they keep out pests which could otherwise damage the plants
  • they make it easier to control the conditions, such as levels of carbon dioxide, fertiliser, water etc
• what are paraffin heaters, and why are they used in greenhouses

  • paraffin heaters burn a fossil fuel called paraffin
  • this produces carbon dioxide and heat energy, both of which help plants to grow
• what is the formula that links light intensity and distance

  $\frac{1}{d^2}$$\infty$I

  I - light intensity (arbitrary units)

  d - distance (m)