Section 4: How a Plant Grows

Glossary

Lesson 3: Respiration



Now that we know how a plant can manufacture its own food through the process of photosynthesis, we are prepared to learn how the plant can go about using this food.
First, think of how animals and humans use food as an energy source to grow and reproduce, and to do many more activities that make up daily life. It's really the same with plants.
Plants use food, glucose made by photosynthesis, for the same reasons animals do-to sustain life. The process is also similar; it consists of the metabolization of mostly glucose.
For plants, the process is called respiration, and it is the exact reverse of photosynthesis. It converts the glucose back into energy for growth and other life processes.

Breathing healthy, fresh air - provided by surrounding plants, is good for the body and good for the psyche.
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Here is a concise statement of what is actually happening in plant respiration:

Once again, the two lines say the very same thing. The second line is the actual chemical equation for the process of plant respiration.


    The following table summarizes the processes of photosynthesis and respiration. It should be obvious that one is the reverse of the other:


    COMPARISON OF PHOTOSYNTHESIS AND RESPIRATION
    Photosynthesis
    		 Respiration
    Produces sugars from light energy
    Burns sugars for energy
    Stores energy
    Releases energy
    Occurs only in cells with chloroplasts
    Occurs in most cells
    Releases oxygen
    Uses oxygen
     Uses water
    Produces water
    Uses carbon dioxide
    Produces carbon dioxide
    Requires light
    Occurs in dark and light