• Question: what is photosynthesis?

    Asked by to Amelia, Izzy, Sarah on 19 Mar 2014. This question was also asked by .
    • Photo: Isabel Webb

      Isabel Webb answered on 19 Mar 2014:


      When we need sugar (which we need for energy), we eat some food (like chocolate 🙂 ). Sugar contains energy which living things can release – chemical energy. Plants don’t eat – they need a different way of getting sugars and so energy.

      Plants are able to convert light energy into chemical energy using a process called photosynthesis. Photosynthesis is powered by light. The plant has a chemical called ‘chlorophyll’, which is green. The chlorophyll captures light and uses it to power a chemical reaction. This reaction takes carbon dioxide (from air) and water (from the soil, taken up by roots) and turns them into sugar. The light energy is used to join the two together to make these sugars.

      Once the plant has sugars it either stores them, or breaks them down to release energy to power growth or defence against diseases.

    • Photo: anon

      anon answered on 19 Mar 2014:


      Photosynthesis is the plant’s way of getting energy and growing (synthesizing). Plants are able to convert sunlight (photo)

      so photosynthesis is effectively creating by light.

      This is a complex chemical process 😛

    • Photo: Amelia Frizell-Armitage

      Amelia Frizell-Armitage answered on 20 Mar 2014:


      Photosynthesis is the chemical reaction that plants use to make energy for themselves.

      During photosynthesis plants take carbon dioxide from the air and use light energy to react this with water. This reaction produces oxygen and glucose. Glucose is a sugar which when broken down releases lots of energy. The glucose produced in photosynthesis is therefore transported to places in the cell or plant that need it, or stored as starch until a later time when the plant needs energy. The plant does not need the oxygen produced – this is a waste product. Therefore it puts this oxygen back into the air.

      Photosynthesis is essential for plants to produce energy, and also for us as it provides the oxygen we breath!

      Light is made up of 3 different colours – red, blue and green. During photosynthesis plants absorb and use the blue and red light. However they don’t need the green light, so they reflect this. This is why all photosynthesising plants are green!

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