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Information on Photosynthesis

by Suzanne McCullough White
  • Overview

    The word "photosynthesis" means "put together by light." It is the chemical process by which green plants and certain types of algae convert light energy into food and oxygen. Photosynthesis is one of the most important chemical processes on Earth.
  • Plant Anatomy

    All green plants contain "chlorophyll," a green pigment used in the process of photosynthesis. Within the plant's cells are "organelles" (so named because they are a tiny equivalent of the organs inside the body) called "chloroplasts," which are filled with chlorophyll and are the site of photosynthesis. In a plant, chloroplasts are only found in the stems and leaves, and photosynthesis occurs mainly in the upper surfaces of the leaves.
  • Chemistry

    Green plants (and some algae) contain a pigment called "chlorophyll," which is used to trap the sun's energy in a process called "photosynthesis." During this reaction, the plant takes in this light energy, plus water, plus carbon dioxide from the atmosphere and converts them into chemical energy, in the form of sugars. These sugars are then used by the plants as its food source.
  • Process

    The exact equation for photosynthesis is that six molecules of water, plus six molecules of carbon dioxide use energy from the sun to yield one molecule of sugar and six molecules of oxygen. The reaction is a two-part one, with one stage occurring in the light, and the other in the dark. The plant converts energy during the light reaction and stores it during the dark one.
  • Chlorophyll

    Pigments are defined as substances that absorb light. The darker the color, the greater the range of colors that it can absorb. Chlorophyll absorbs all frequencies of light except green, which is why it looks green to our eyes. It is the red and blue pigments that do all the work.
  • Importance

    Photosynthesis by plants is necessary in the environment to get rid of excess carbon dioxide. "Global warming" is a direct result of the increase of carbon dioxide in the atmosphere. Human activity is responsible for this increase, caused by such things as our use of fossil fuels and fertilizers. Plants act as carbon dioxide "sinks" and without them, the atmosphere would not be able to support life.

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