Topics 2.9

Essential idea: Photosynthesis uses the energy in sunlight to produce the chemical energy needed for life.


2.9.U1 Photosynthesis is the production of carbon compounds using light energy

Equation Photosynthesis

2.9.U2 Visible light has a range of wavelengths with violet the shortest wavelength and red the longest

Different wavelengths of light

2.9.U3 Chlorophyll absorbs red and blue light most effectively and reflects green light more than other colours

Absorption of light by chlorophyll

The differences in absorption of red, blue and green light by chlorophyll

Place mouse pointer on the figure to show the explanation of absorption of red, blue and green light.


2.9.U4 Oxygen is produced in photosynthesis from the photolysis of water

Splitting of water

2.9.U5 Energy is needed to produce carbohydrates and other carbon compounds from carbon dioxide

Using energy to produce carbohydrates

Overview of Photosynthesis


2.9.U6 Temperature, light intensity and carbon dioxide concentration are possible limiting factors on the rate of photosyntesis

Limiting Factors and the photosynthetic rate:

Effects of carbon dioxide as a limiting factor on photosynthetic rate

carbon dioxide graph

Effects of light intensity as a limiting factor on photosynthetic rate

light intensity graph

Effects of temperature as a limiting factor on photosynthetic rate

temperature graph


2.9.A1 Changes to the Earth's atmosphere, oceans and rock deposition due to photosynthesis

Changes in the atmosphere and oceans due to photosynthesis


2.9.S1 Drawing an absorption spectrum for chlorophyll and an action spectrum for photosynthesis

Know how to draw the graphs for absorption spectrum and action spectrum!

Graph of action spectrum

2.9.S2 Design of experiments to investigate the effect of limiting factors on photosynthesis

Go to Internal Assessment: Design

2.9.S3 Separation of photosynthetic pigments by chromatography

Paper chromatography link Paper chromatography video
Thin layer chromatograpy link glycolysis animation
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