Download Photosynthesis in Action

Photosynthesis in Action
Setting the Scene
Photosynthesis is the means by which plants can convert carbon dioxide and water to oxygen
and, most importantly, glucose. This happens when sunlight hits a pigment called chlorophyll,
which is stored in the chloroplasts in plant cells.
Plants then use the glucose in a number of different ways:
- Respire the glucose to provide energy
- Use glucose as a building block for making cellulose, which is used for producing cell walls.
- Store the glucose as starch, so that the plant can use the glucose at another time.
- Combine with other molecules to make either fatty acids or amino acids.
There are a number of
factors which affect the rate
of photosynthesis, and one of
them is light intensity. This
interactive science
experiment allows us to
discover the relationship
between these.
We can measure the rate of photosynthesis in a number of ways, and one of them is to use an
underwater plant, such as Canadian pondweed (Elodea canadensis). We can then count the
number of bubbles being released from the plant each minute.
Your Challenge
1. Complete the online experiment on
www.syngenta.co.uk/learningzone. The
method of how to measure the rate of
photosynthesis is included with the
experiment. Remember that the more
measurements you take at each distance
away from the light, the more accurate and
reliable your data will be.
relate to the light intensity?
4. What gas do you think the bubbles contain?
5. Using your data and your graph, describe the
trend that it shows. Why do you think this
trend occurs?
6. Can you think of any other factors, apart from
light intensity, which could affect the rate of
photosynthesis in Elodea canadensis? How
2. Plot your results on a graph, with suitable
do these factors affect photosynthesis?
length axes and a meaningful title. Remember
to state what is being measured on each axis, 7. How could you improve this experiment to
and to include units of measurement.
achieve more precise, accurate and reliable
results?
3. How does the distance from the light source
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