Themes of Plant Biology
Photosynthesis
Photosynthesis is the process by which organisms convert light energy into chemical energy. The most common and critical type of photosynthesis takes place in chlorophyll-containing
plants, algae, and
cyanobacteria. These organisms capture radiant energy of the sun and, by utilizing carbon dioxide and water, convert it to chemical energy stored in molecules of carbohydrates. Oxygen and water are released as by-products. The generalized equation is:
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The other photosynthesizers are green and purple bacteria, which convert light energy to chemical energy, but use other raw materials and pigments in an oxygen-free ( anaerobic) environment to make carbohydrates. Different by-products result.
A generalized equation for
all kinds of photosynthesis therefore is:
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Photosynthesis is the single most important process on earth, for without it neither plants nor animals (including humans) could survive. The energy stored in organic molecules by photosynthesizers is the fuel of life for most living things and the oxygen released during photosynthesis makes cellular respiration—and therefore life—possible on earth.
