Wednesday, 20 February 2013

2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll

The most common experiment for this is using pond weed, which is placed under water then factors are varied:
A lamp is moved further from the plant;
Baking powder is added to the water (increasing CO2);
A white leaved plant is tested against a green leaved plant (green has more chlorophyll).

The gas it gives off- being the products of photosynthesis- is counted as bubbles or measured by downwards displacement. This shows the speed of photosynthesis under different conditions.
Iodine can be used to test the production of starch.
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9 comments:

  1. William2 April 2015 at 03:45

    What organism is investigated when looking at starch production?

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    Replies
    1. HannahHelp17 June 2015 at 16:14

      When I did it it was just with a green leaf

      Delete
  2. Unknown10 May 2015 at 06:02

    Plants because they store energy as starch, but animals and fungi store energy in glycogen.

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  3. Unknown10 May 2015 at 06:03

    Good luck to everyone on Tuesday btw :)

    ReplyDelete
  4. Unknown11 May 2015 at 13:12

    GOD LUCK TOMOROOW IF U HAVE UR GCSES

    ReplyDelete
  5. Unknown31 May 2017 at 14:08

    u need to add in more on iodine tests. u can check p.109-110 of the edexcel 2009 edition

    ReplyDelete
  6. SophieRice26 June 2017 at 17:53

    more at

    http://igcse-biology-notes.blogspot.hk/2017/06/222-describe-experiments-to-investigate.html

    ReplyDelete

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