1. Lesson Objectives:
Define what a limiting factor is.
Describe how a particular factor can affect the rate of photosynthesis.
~ Explain how you could carry out a practical investigation to test how these factors affect the rate

2. A limiting factor is...
Part of the photosynthesis reaction that is in short supply which prevents the rate of photosynthesis increasing further.

3. LIMITING Have you got the....
As group use your information sheet on your ‘Limiting Factor’ to create a poster displaying what you have found out.
Your poster should include:
~ your limiting factor
~ a graph
~ explain how the limiting factor affects the rate of photosynthesis
~ an investigation you could carry out to test this limiting factor
No more than 10 words! Feel free to use as many symbols and diagrams though!
Have you got the....
LIMITING
Then you will audition your limiting factor to the rest of the class by showing your poster and explaining what you found out about your limiting factor.

4. Limiting Factors Which Affect The Rate of Photosynthesis
Audition Number 1
‘Have you got the limiting factor?! Light Intensity
Why is light needed for photosynthesis?
What happens to the rate of
photosynthesis when light intensity is
increased?
What investigation could you carry out?
Could different colors of light affect the rate? Why do leaves appear green? Think about using coloured filters!
Without enough light, a plant cannot photosynthesise very quickly, even if there is plenty of water and carbon dioxide.

5. Limiting Factors Which Affect The Rate of Photosynthesis
Audition Number 2 ‘Have you got the limiting factor?!’ Carbon Dioxide Concentration
What happens to the rate of photosynthesis when the concentration of carbon dioxide is increased?
How could we carry out an investigation to test this limiting factor?
Carbon dioxide levels can be increased by burning carbon-based fuels (e.g. Natural gas) or using tanks of pure carbon dioxide.
Carbon dioxide levels in the air are approximately 0.03%

6. Limiting Factors Which Affect The Rate of Photosynthesis
Audition Number 3 ‘Have you got the limiting factor?!’ Temperature
What happens to the rate of photosynthesis when the temperature is increased? Why?
What investigation could you carry
out to test this limiting factor?
Increasing temperature provides particles
with more energy.
Temperatures approximately above 35°C
cause enzymes to denature. °C °C

7. Limiting Factors Which Affect The Rate of Photosynthesis
Audition Number 4 ‘Have you got the limiting factor?!’ Can your knowledge of limiting factors maximise plant growth?!
Farmers can use their knowledge of these limiting factors to increase crop growth in greenhouses.
They may use artificial light so that photosynthesis. They also use paraffin lamps which produces carbon dioxide and heat too. How could these increase the rate of photosynthesis?
What are the advantages to farmers of using these methods? Think about times of the day and year!
Could farmers continually keep increasing the rate of photosynthesis? Or is there another limiting factor? Think about inside the plant!

8. Limiting Factors and the Rate of Photosynthesis
A limiting factor is...

9. http://www.youtube.com/watch?v=4bAMdLEq7Dg xfactor theme tune