Science / Is Carbon Dioxide Necessary For Photosynthesis?

Is Carbon Dioxide Necessary For Photosynthesis?

Autor:  moto  08 March 2011
Tags:  science
Words: 439   |   Pages: 2
Views: 4784

AIM

To determine if carbon dioxide (CO2) is necessary for starch production

HYPOTHESIS

The iodine will react with the leaf that contains carbon dioxide (CO2) instead of the leaf that does not contains CO2.

BACKGROUND

Photosynthesis occurs in most plants that make their own food. Carbon dioxide is obtained through the plants stomata whereas oxygen is released through the stomata. Water is obtained by the plant through the roots and delivered to the leaves through the xylem tissue in the stem to the veins in the leaf. Chlorophyll, a green pigment located in chloroplasts and light is needed as shown in the equation below because the chlorophyll of the leaf traps the light energy, and therefore converting the energy to chemical energy. The chemical energy is then stored in the form of glucose. Therefore, the equation for photosynthesis can be written as:

Chlorophyll

6CO2 + 6H2O  C6H12O6 + 6O2

carbon dioxide water Sunlight glucose oxygen

To determine whether carbon dioxide is needed for photosynthesis, a test for starch could be carried out. When iodine solution is stained on the leaf, the green part of the leaf will turned blue black. This means that starch is present. If starch is present, the process of photosynthesis has occurred. From the equation above, glucose is produce in the process of photosynthesis. However, in plants, glucose is converted to starch. This is because starch is insoluble in water and it is a large molecule, which cannot diffuse through the cell membranes.

MATERIALS

1. One leaf

2. Beaker

3. Hot pot

4. Petri dish

5. Methylated spirits

6. Iodine solution

7. Forceps

8. White tile

PROCEDURE

Two leaves were taken from two different plants. One leaf was taken from a potted plant which was exposed to the atmosphere that contains carbon dioxide. Another leaf was taken from a plant that was covered with a plastic bag and contains soda lime that absorbs carbon dioxid...



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