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The Light-Dependent Reactions of Photosynthesis

6 April, 2016 - 17:26

Learning Objective

By the end of this section, you will be able to:

  • Explain how plants absorb energy from sunlight
  • Describe how the wavelength of light affects its energy and color
  • Describe how and where photosynthesis takes place within a plant

How can light be used to make food? It is easy to think of light as something that exists and allows living organisms, such as humans, to see, but light is a form of energy. Like all energy, light can travel, change form, and be harnessed to do work. In the case of photosynthesis, light energy is transformed into chemical energy, which autotrophs use to build carbohydrate molecules. However, autotrophs only use a specific component of sunlight (Figure 5.8 ).

Figure 5.8
Autotrophs can capture light energy from the sun, converting it into chemical energy used to build food molecules. 


Visit this site ( and click through the animation to view the process of photosynthesis within a leaf.