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An Experiment with Photosynthesis Essay

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Title
A study to investigate the effect of varying light intensities on the rate of photosynthesis and oxygen production.

Introduction
Photosynthesis is a multistep process where light energy is converted into chemical energy (G.Garab 1998). It takes place within the chloroplasts in the plants and involves two major steps; light dependent reactions and light independent reactions. Photosynthesis results in the release of oxygen and the removal of carbon dioxide from the atmosphere, which is then used to synthesize carbohydrates. The overall chemical equation is 6CO2 + 6H20 --> C6H12O6 +6O2 (J.Kohler 1998). When carbon dioxide is reduced it affects the rate of photosynthetic electron transport and therefore the rate of oxygen …show more content…

Figure 1 shows the measured rate of oxygen production fall below zero. This is because oxygen is being consumed in the dark due to respiration.
Discussion
At the light intensity of 0 μg O2 L-1 s-1 the measured rate of oxygen production was approximately -2 which indicated that there was oxygen being consumed. Light independent reactions drive the assembly of carbohydrates (sugar molecules) from carbon dioxide using energy harvested during the light reaction. Light dependent reactions in the thylakoid use light energy to produce ATP and NADPH. A light independent, so known as the Calvin cycle use the energy from the molecules to make Glyceraldehyde-3-phosphate (GA3P) from carbon dioxide.
Cellular respiration allows the plants to release the energy stored in the chemical bonds of glucose and this energy (in the form of ATP) is used to supply a plants energy needs. In respiration the oxygen reduced to form water hence why the oxygen is consumed in the dark.

The line passing through the x-axis indicates the reaction has reached the ‘photosynthetic compensation point’ [R]. This means that the uptake of oxygen by respiration exactly matches the amount of oxygen being released by photosynthesis.
Between 0 and 150 photons m-2s-1, the rate of oxygen production is steadily increasing in a linear fashion. Past 150 photons m-2s-1 it beings to

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