Essential idea: Photosynthesis uses the energy in sunlight to produce the chemical energy needed for life.
Above is an microscope image of leaf cells. You can clearly see the cells are packed with chloroplasts. These specialised organelles contain chlorophyll (and other pigments) which trap light energy and use it to build glucose molecules.
Understandings, Applications and skills
| 2.9.U1 | Photosynthesis is the production of carbon compounds in cells using light energy. |
| 2.9.U2 | Visible light has a range of wavelengths with violet the shortest wavelength and red the longest. |
| 2.9.U3 | Chlorophyll absorbs red and blue light most effectively and reflects green light more than other colours. [Students should know that visible light has wavelengths between 400 and 700 nanometres, but they are not expected to recall the wavelengths of specific colours of light.] |
| 2.9.U4 | Oxygen is produced in photosynthesis from the photolysis of water. |
| 2.9.U5 | Energy is needed to produce carbohydrates and other carbon compounds from carbon dioxide. |
| 2.9.U6 | Temperature, light intensity and carbon dioxide concentration are possible limiting factors on the rate of photosynthesis. |
| 2.9.A1 | Changes to the Earth’s atmosphere, oceans and rock deposition due to photosynthesis. |
| 2.9.S1 | Drawing an absorption spectrum for chlorophyll and an action spectrum for photosynthesis. |
| 2.9.S2 | Design of experiments to investigate the effect of limiting factors on photosynthesis. [Water free of dissolved carbon dioxide for photosynthesis experiments can be produced by boiling and cooling water.] |
| 2.9.S3 | Separation of photosynthetic pigments by chromatograph. (Practical 4) [Paper chromatography can be used to separate photosynthetic pigments but thin layer chromatography gives better results.] |
[Text in square brackets indicates guidance notes]
Starter
A bit of fun - a rap about photosynthesis by US High school students studying Biology
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Below are the notes for this topic. Alternatively the 2.9 Photosynthesis notes - the bottom line template can be used as a note construction template in itself or as a checklist if you are using your own or another template such as the Cornell style template.
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Weblinks
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Absorption and action spectra
Pigments and the absorption of light by S-Cool Photosynthesis Photosynthesis by Biocoach Photosynthesis by the University of Alberta |
Virtual labs
Photosynthesis by McGraw and Hill shows the Generation of ATP by the light dependent reactions Photosynthesis Virtual Experiment by Reading University Which colours of light are most important for photosynthesis by Glencoe Plant pigments and photosynthesis by LabBench |
Nature of science
Experimental design—controlling relevant variables in photosynthesis experiments is essential. (3.1) [Related to 2.9.S2, covered in the presentation]
