What affects the rate of photosynthesis in Elodea?

Authors Avatar

Biology Coursework

What affects the rate of photosynthesis in Elodea?

   Aim: To find out which factors affect the rate of photosynthesis in Elodea.

   Variables: The variables that might affect the rate of photosynthesis in this experiment are:

  Temperature: When the temperature rises so does the rate of photosynthesis; this is because as the temperature around the plant rises the enzymes controlling photosynthesis inside the chloroplasts heat up and start moving around faster, the fast moving molecules collide with other fast moving enzymes causing them to react.

 The rate of diffusion of carbon dioxide into the leaves will also ride as temperature does. This happens because fast moving carbon dioxide molecules will hit the surface of the leaf far more often than in a colder atmosphere therefore more molecules will be taken into the leaf and diffusion will happen faster. However, the rate of photosynthesis will only keep on rising until the temperature reaches 45’c at that temperature the enzymes in the chlorophyll will be destroyed and photosynthesis will stop all together. On the other hand, if the temperature is too cold then temperature will become the limiting factor and the enzymes will stop working.

 

   Carbon dioxide: The amount of carbon dioxide in the atmosphere around the elodea affects the rate at which it will photosynthesise. The plant needs carbon dioxide to react with water molecules to make glucose. If there isn’t enough carbon dioxide for the plant to take in the plant wouldn’t have enough glucose or food and would die. For the plant to keep on photosynthesising at a steady rate there needs to be plenty of water and the temperature needs to be kept at a certain level because once carbon dioxide is no longer the limiting factor simply giving the plant more wont have any effect.

   

  Light intensity: It is impossible for plants to photosynthesise in the dark and they can only photosynthesise slowly in dim light, this is because the light energy splits up the water into hydrogen and oxygen it does this by releasing a highly charged electron when sunlight is absorbed, the electron lost by the chlorophyll is replaced by an electron from water to change water from H20 into ½ 02 + 2H+, o2 is released as a by product and the hydrogen is used to react with carbon dioxide to make C6H12O6 (glucose). This can only happen as fast as the light is arriving so it can only work efficiently if there is plenty of light to be absorbed.

   

  Light colour: Certain colours of light can change the rate of photosynthesis in green plants such as elodea depending on how well the light can be absorbed into the plants chlorophyll. Chlorophyll is green because it can only absorb the red and blue lights at either end of the visible spectrum, it reflects off the green light in the middle because it cannot be absorbed. If we put a light with a green filter to the elodea the plant would not be able to photosynthesise simply because there would be no light energy available that the elodea could absorb.

Join now!

   

   Size of elodea: The rate of photosynthesis can vary depending on the size of the elodea the rate of photosynthesis will increase. The bigger the surface area of the plant the more palisade cells. The palisade cells is where the chloroplasts are and furthermore where photosynthesis takes place. So if there is a big Elodea plant the speed that photosynthesis happens will increase as there are more palisade cells that can be photosynthesising

I have decided to explore into how light intensity affects the rate of photosynthesis in the elodea. To do this I will carry ...

This is a preview of the whole essay