The different factors that affect the rate of photosynthesis.
Introduction:
Within this unit we will be exploring how carbon dioxide affects the rate of photosynthesis.
Photosynthesis is the process of converting light energy to chemical energy and storing it in the
bonds of sugars for plants to use.
Light intensity:
When light intensity increases the rate of photosynthesis generally increases proportionally. This is
mainly due to the fact that, the more photons of light that fall on a leaf, the greater the number of
chlorophyll molecules that are ionised and the more ATP and NADPH are generated. Light
dependent reactions use light energy and so are not affected by changes in temperature. As light
intensity is increased further, the rate of photosynthesis is eventually limited by some other factor.
This causes the rate to plateaus. At very high light intensity, chlorophyll may be damaged and the
rate drops steeply. Chlorophyll a is used in both photosystems. The wavelength of light is also
important. PSI absorbs energy most efficiently at 700 nm and PSII at 680 nm. ( Bowzin A 2014)
Temperature:
Although the light dependent reactions of photosynthesis are not affected by changes in
temperature, the light independent reactions of photosynthesis are. They are reactions catalysed by
enzymes. As the enzymes approach their optimum temperatures the overall rate increases. It
approximately doubles for every 10 °C increase in temperature. Above the optimum temperature
the rate begins to decrease, due to the enzymes being denatured. ( Bio Academy 2019).
Carbon dioxide:
An increase in the concentration of carbon dioxide increases the rate at which carbon dioxide is
incorporated into carbohydrate during the light independent reaction. This causes the rate of
photosynthesis to increase until it is limited by another factor.
Carbon dioxide within the atmosphere is found at very low concentrations, around 0.04%.
Therefore, increasing the concentration of carbon dioxide has a significant impact on the rate of
photosynthesis. It increases very quickly until the maximum rate of fixation is reached where it then
plateaus. (Bio Academy 2019).
Hypothesis:
By increasing the concentration of carbon dioxide within the water, it will increase the rate
of photosynthesis. This is because the concentration of carbon dioxide required for the
creation of carbohydrates during the light-independent reaction will be increased. This
would then lead to more carbohydrates being produced in a shorter amount of time. This is
due to there being more carbon dioxide readily available for fixation to occur at an
increased rate.
Null hypothesis:
Introduction:
Within this unit we will be exploring how carbon dioxide affects the rate of photosynthesis.
Photosynthesis is the process of converting light energy to chemical energy and storing it in the
bonds of sugars for plants to use.
Light intensity:
When light intensity increases the rate of photosynthesis generally increases proportionally. This is
mainly due to the fact that, the more photons of light that fall on a leaf, the greater the number of
chlorophyll molecules that are ionised and the more ATP and NADPH are generated. Light
dependent reactions use light energy and so are not affected by changes in temperature. As light
intensity is increased further, the rate of photosynthesis is eventually limited by some other factor.
This causes the rate to plateaus. At very high light intensity, chlorophyll may be damaged and the
rate drops steeply. Chlorophyll a is used in both photosystems. The wavelength of light is also
important. PSI absorbs energy most efficiently at 700 nm and PSII at 680 nm. ( Bowzin A 2014)
Temperature:
Although the light dependent reactions of photosynthesis are not affected by changes in
temperature, the light independent reactions of photosynthesis are. They are reactions catalysed by
enzymes. As the enzymes approach their optimum temperatures the overall rate increases. It
approximately doubles for every 10 °C increase in temperature. Above the optimum temperature
the rate begins to decrease, due to the enzymes being denatured. ( Bio Academy 2019).
Carbon dioxide:
An increase in the concentration of carbon dioxide increases the rate at which carbon dioxide is
incorporated into carbohydrate during the light independent reaction. This causes the rate of
photosynthesis to increase until it is limited by another factor.
Carbon dioxide within the atmosphere is found at very low concentrations, around 0.04%.
Therefore, increasing the concentration of carbon dioxide has a significant impact on the rate of
photosynthesis. It increases very quickly until the maximum rate of fixation is reached where it then
plateaus. (Bio Academy 2019).
Hypothesis:
By increasing the concentration of carbon dioxide within the water, it will increase the rate
of photosynthesis. This is because the concentration of carbon dioxide required for the
creation of carbohydrates during the light-independent reaction will be increased. This
would then lead to more carbohydrates being produced in a shorter amount of time. This is
due to there being more carbon dioxide readily available for fixation to occur at an
increased rate.
Null hypothesis:
