rate of photosynthesis

• | light

  
  

  • provides energy for photosynthesis
  • as light increases, photosynthesis increases steadily to a certain point
  • beyond that, it won’t make a difference bc either temperature or CO2 is the limiting factor
• | light

  
  

  measure light intensity with a light meter
• | carbon dioxide

  • one of the raw materials needed for photosynthesis
  • similar to light, it will increase to a certain point until either light or temperature is a limiting factor
• | temperature

  • usually if temperature is a limiting factor, it’s because it’s TOO LOW; ENZYMES needed work slowly at low temperatures
  • if too HOT, enzymes are DAMAGED
  • happens at ≈ 45°C
• approximately, at what temperature do enzymes get damaged

  45 degrees
• what can you measure light with?

  light meter
• if light and CO2 concentration isn’t a limiting factor, what the limiting factor?

  temperature
• greenhouse gases can reach up to 45 degrees which can denature enzymes
• | pondweed practical

  1. light placed at specific distance from pondweed
  2. let it photosynthesise for a set amt of time
  3. @ end, syringe draws gas bubbles in tube alongside the ruler & LENGTH of gas bubble is measured = volume of O2
• | pondweed practical

  • any VARIABLES affecting results should be controlled eg: temp & time pondweed photosynthesises
  • repeat twice to calculate mean

  
• | inverse square law

  light density = 1/d^2
• | artificially cr8ing ideal conditions

  • most common way is growing in GREENHOUSES
  • help TRAP sun’s HEAT so temperature doesn’t become LIMITING
  • winter: use HEATER_ summer: shades & ventilation
  • LIGHT always needed for photosynthesis; can supply w/ ARTIFICIAL LIGHT when sun’s down
• | artificially cr8ing ideal conditions

  • PARAFFIN HEATER increases CO2 levels
  • keeping plants enclosed = free from PESTS & DISEASES
  • can add FERTILISERS to soil to provide MINERALS
• | artificially cr8ing ideal conditions

  • sorting greenhouses COSTS MONEY but can produce plants FASTER and harvest more OFTEN for MONEY
• what can be used to increase carbon dioxide levels in a greenhouse?

  parrafin heater
• what can farmers do to supply light when the sun isn’t present?

  artificial light
• what can farmers do during the summer to make sure the temperature isn’t too high?

  use shades and ventilation
• what can farmers do during the winter to make sure the temperature isn’t too low?

  use a heater
• what do greenhouses do

  trap the sun’s heat so temperatures aren’t limiting