Transcript Photosynthesis - Noadswood Science

Photosynthesis
L.O: To know the limiting factors for photosynthesis
and explain how they affect the rate of photosynthesis.
Be able to draw sketch graphs to show effect of limiting
factors.
Photosythesis song
Watch the video. Click on
www.vimeo.com/35073724
1. Write down the word equation.
2. Write down the symbol equation.
Weight Gain
• Plants make their own food via photosynthesis (chlorophyll in the
leaves) with the energy coming from the Sun
light energy
chlorophyll
carbon dioxide
(from the air)
Glucose (used by
the plant)
water
(from the soil)
Oxygen (given out)
Photosynthesis
• This is the process of food production for the plant
(producing biomass) and requires the leaves to take
place…
chlorophyll
light energy
carbon dioxide + water  glucose + oxygen
6CO2 + 6H2O  C6H12O6 + 6O2
Limiting factors
• List 4 factors that affect the rate of
photosynthesis? Explain why.
1. Light intensity
2. Temperature - Click on the video link to find
out more
http://espresso/espresso/clipbank/servlet/asset?assetID=4729
3. Amount of carbon-dioxide
4. Amount of water
A sketch graph includes title and
a line of best fit ( no need to
worry about units and scale).
Sketch graph 1
2
1
3
Task 1 : Draw the graph (in
pencil) then describe the
graph (it’s pattern or shape)
at stages 1, 2 and 3.
Suggest what limiting
factors cause the graph to
level off (stage 3)
Photosynthesis and light – limiting factors
rate of photosynthesis
How does the amount of light affect the rate
of photosynthesis on this labelled graph?
1
2
2
1
light intensity
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As the amount of light
increases, the rate
increases quickly . The
limiting factor is light.
Here, increasing the amount
of light has no affect on the
rate. The limiting factor is
now carbon dioxide or
temperature.
What must be increased for
the rate to increase?
© Boardworks Ltd 2004
Sketch graph 2
Task 2 : Draw the graph (in
pencil) then describe the
graph (it’s pattern or shape) in
as much detail as you can.
Suggest what limiting factors
cause the graph to level off
(stage 3)
Photosynthesis and carbon dioxide – limiting factors
rate of photosynthesis
How does the amount of carbon dioxide affect
the rate of photosynthesis on this labelled graph?
As the amount of carbon
dioxide goes up, so does
the rate. The limiting
factor is carbon dioxide.
2
Here, increasing the
amount of carbon dioxide
has no affect on the rate.
Light or warmth is now
the limiting factor.
2
1
concentration of
carbon dioxide
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1
What must be increased
for the rate to increase?
© Boardworks Ltd 2004
Sketch graph 3
Task 3: Draw the graph (in
pencil) then describe the
graph (it’s pattern or shape) in
as much detail as you can.
Suggest why this graph is a
different shape.
Photosynthesis and temperature – limiting factors
rate of photosynthesis
How does temperature affect the rate of
photosynthesis on this labelled graph?
2
1
0oC temperature 45oC
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11. As temperature increases,
so does the rate because
photosynthetic enzymes
work best in the warmth.
Here, the limiting factor is
temperature.
2
Most plant enzymes are
denatured (change shape)
at about 45°C. Here,
photosynthesis stops and
the rate falls to zero.
What is the limiting factor?
© Boardworks Ltd 2004
Limiting factors activity
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© Boardworks Ltd 2004
Limiting factors in the greenhouse
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© Boardworks Ltd 2004
Anagrams
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© Boardworks Ltd 2005
2004