Respiration only occurs in animals, plants photosynthesize for energy.

A common misconception about plants is that they photosynthesize to provide energy for their cells. Photosynthesis does in fact produce glucose molecules that provide the foundation for energy use, but it isn’t the process that makes useable energy. Cellular respiration is an essential part of life for both animals and plants. This process occurs in the mitochondria by breaking down glucose molecules and releasing energy in the form of ATP. ATP molecules are then used throughout the cell for many necessary processes.


Where is this misconception born?

This misconception, unlike many others, begins in the science classroom. Teaching literature provided in pre-college curriculum contains misleading information. Even though this inaccurate material would be easily identified by a botany teacher, most life science teachers have very little training in the botany field. Often teachers only explain photosynthesis during a plant unit and then move on to cellular respiration when they begin to talk about animals. Teachers likely discuss the importance of cellular respiration for all living organisms, but it may be too late. Students have already placed photosynthesis with plants and cellular respiration with animals.

How can we avoid promoting this misconception?

In any life science course the process of energy transfer is discussed. When talking about primary producers (plants) a teacher should emphasize why plants build glucose molecules. Teachers should be aware that plants photosynthesize for their own energy needs and not for our (animals) benefit. Teachers should avoid discussing energy transfer in an ecosystem until students are familiar with the processes that occur in a plant cell. One useful activity teachers can use to help students understand these interrelated processes is to have students build a self-contained ecosystem. Students can place soil, water and a plant into a closed bottle and watch the plant grow. During the design of this project students should be asked probing questions such as “How will your plant get carbon-dioxide to use for photosynthesis?” and “How long do you think your plant can live in there?”.


Fun Science Gallery: Environmental education and biology


Action Bioscience: Avoid misconceptions when teaching about plants. Hershey, David R.