Rate of Photosyntesis

Rate of Photosynthesis:

Background:

In the process of photosynthesis, light energy is converted into chemical energy. The raw materials needed are carbon dioxide and water, and the energy source is sunlight. The product of photosynthesis – usually carried out by plants containing chloroplasts – is oxygen and carbohydrates, for example sucrose, glucose and starch. Photosynthesis occurs in the chloroplast, an organelle in plant cells that contains the molecule chlorophyll. Chlorophyll absorbs the energy of sunlight.

There are many limiting factors that could affect the rate of photosynthesis. Light intensity, carbon dioxide concentration and temperature are three factors that can determine the rate of photosynthesis. If the level of one of these factors is changed, the rate of photosynthesis changes accordingly. The overall rate of photosynthesis in a plant is determined by the rate of whichever step is proceeding most slowly at a particular time. During the process of forming glucose (photosynthesis), carbon dioxide combines with water and oxygen is released as a waster product. If a lot of oxygen is given off as a waste product, then we can deduct that photosynthesis is occurring rapidly. If little oxygen is being given off, then we can assume that the rate of photosynthesis is slow. In this way, we can assume that if carbon dioxide is absorbed at a rapid rate in the water, then the rate of photosynthesis is also rapid.

In this lab we will be focusing on the effect of light intensity on the rate of photosynthesis. As light intensity increases, the photosynthetic rate increases until it reaches the optimum point, after which it levels off. At low light intensity photosynthesis occurs slowly because only a small quantity of ATP and NADPH is created by the light independent reactions. As light intensity increases, more ATP and NADPH are created, thus increasing the photosynthetic rate. The use of sodium...