What Role Does Water Play in Photosynthesis?
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How Photosynthesis Works
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Plants use a process called photosynthesis to create food. It requires a combination of water, light energy and carbon dioxide for the chemical reaction to take place. In order for photosynthesis to be successful, each of these elements muse be present in the correct proportion. While light energy and carbon dioxide are freely accessible from the air surrounding the plant, water must be absorbed through the roots and may be scarce during dry seasons. The roots of plants extend into the earth in order to have access to moisture under the surface. Once the roots have absorbed water, it is transported up the plant into the leaves by structures called xylem. The water within the plant is not only directly necessary for photosynthesis, but also for preserving water in the plant by periodically closing the stomata.
Stomata
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The stomata are structures in the leaves that open to facilitate photosynthesis by letting in carbon dioxide and letting out oxygen. While they are open, however, water vapor can escape. The stomata can be closed by guard cells, which surround them. In order for the guard cells to be closed, they must swell with water. Without enough water, the stomata cannot be closed, which results in more severe dehydration for the plant and an inability to proceed with photosynthesis.
Creating Sugar
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Once the sun's energy has been absorbed by chlorophyll, and other pigments within the leaves, it is converted into adenosine triphosphate, typically referred to as ATP. ATP is a chemical that stores energy to be used in the light-independent phase of photosynthesis.The stored energy is used to excite and combine six molecules of carbon dioxide (CO2) and six molecules of water (H2O) to make one molecule of sugar (C6H12O6). It leaves an extra six molecules of oxygen (O) behind to be released from the leaves of the plant.
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