Investigating the effect of temperature on photosynthesis - page 1
Keywords: Investigating the effect of temperature on photosynthesis
By Carlitob10 on 04/11/2006 12:01:11
Level: A Level (Year 13)
Page Number: 1 of 9 pages: 1 2 3 4 5 6 7 8 9
Investigating the effect of temperature on photosynthesis
Aim: to investigate the effect of temperature on the rate of photosynthesis of elodea.
Background Information
Photosynthesis is the use of light energy from the sun to fix carbon dioxide i.e. converted to sugars. These sugars can then be converted into other essential substances- fats and proteins etc. - which plants need to live and grow. The rates of photosynthesis are affected by three factors: concentration of carbon dioxide, light intensity and temperature. If one of these factors increase, the rate of photosynthesis will increase but only to a certain point. The rate of photosynthesis could still increase but not because of an increase in that same factor. Another factor has to increase for the rate to increase. The factor that restricts the other two factors from increasing the rate of photosynthesis is called the limiting factor.
Photosynthesis can be represented using the following equation:
6CO2 + 6H2O C6H12O6 + 6O2
Photosynthesis takes place mainly in leaves and depends on an important green pigment called chlorophyll, which is found in chloroplasts. To obtain the most sunlight as possible, leaves have a large surface area and the more sunlight the plant receives, the better it can photosynthesize. Chloroplasts are found in palisade cells in large numbers and to allow as much light to get in as possible, the cells are arranged like a fence. This helps the energy entering the surface of the leaf to travel a long way through the palisade cells.
The light independent stage occurs in the stroma. Firstly CO2 combines with a 5C compound called ribulose bisphosphate. This reaction is catalysed by the enzyme RuBPC. The 6C compound formed immediately splits into two molecules of glycerate-3-phosphate (GP). The GP molecules are converted into molecules of triose phosphate (TP) using energy from ATP and the hydrogen atom from NADPH. Some of the TP is used to regenerate RuBP. Finally the rest of the TP is used to produce other essential substances that the plant needs- fats, proteins etc.
For glucose to be made in photosynthesis, water is split into hydrogen and oxygen molecules by the energy absorbed from the sun. The hydrogen then has to combine with the carbon dioxide to produce glucose. If this was left on its own, the hydrogen would eventually combine with the carbon dioxide but it would take
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