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How Organisms With Photosynthesis Capture the Energy in Sunlight

Photosynthesis is the process of synthesizing organic materials using sunlight as a source of energy. Plants, some types of bacteria and algae use the process of photosynthesis to turn the energy from sunlight into energy for production of carbohydrates made from carbon dioxide, water and inorganic salts. The types of organisms that use sunlight energy are cyanobacteria and green plants, photosynthetic eubacteria and halobacteria. Photosynthetic organisms use carbon dioxide to make carbohydrates and, in the process, release oxygen into our atmosphere.

Types of Photosynthesis
- There are three ways that organisms use photosynthesis to convert sunlight to energy for food production. C3 photosynthesis is the most common method. C3 photosynthesis is used by most plants to produce a 3-carbon compound. C4 photosynthesis is the method used by plants, including many summer annuals, that produce a 4-carbon compound. C4 photosynthesis requires less energy to produce carbon compounds than the other types of photosynthesis. Succulents use CAM photosynthesis to store carbon dioxide as an acid before eventually using it in photosynthesis.
Stages of Photosynthesis
- Photosynthesis begins when light is absorbed into the organism. Particles of sunlight, called photons, are absorbed by the cells of the plant where they are used as an energy source for converting carbon dioxide into food. Photons stimulate chlorophyll and electrons in the plant cell. The electrons are transported through the plant cell in a series of electrochemical reactions that produce adenosine triphosphate, a sugar-phosphate compound. The second stage of photosynthesis is the conversion of carbon dioxide into oxygen. Water molecules are split during this process to produce carbon dioxide and oxygen. The oxygen is waste that is released from the organism into the air.
Cellular Respiration
- Cellular respiration, the opposite of photosynthesis, is the process by which food is converted to energy. Plants use photosynthesis to produce glucose, or sugar, that is used for energy. During cellular respiration, oxygen is used to produce energy and carbon dioxide is released as waste.
Benefits of Photosynthesis
- Human beings require carbohydrates such as glucose, which our bodies cannot create on their own. People rely on plants that produce these carbohydrates for food. Plant photosynthesis produces the oxygen that we breathe. Phytoplankton in the oceans are responsible for about one half of photosynthesis on Earth. They contribute to the global carbon cycle that is critical to the climate. The photosynthesis process also reduces the amount of carbon dioxide in the air because plants use carbon dioxide to help fuel the process of photosynthesis.

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