Expert: Dana Krempels, Ph.D. - 5/18/2007

Question
Why do plants need oxygen?
I know they produce it but i did not know they needed it.

Answer
Dear Nicole,

All living things that break down sugar to use its energy for doing cellular work need oxygen.  That's because the chemical reactions for breaking down the sugar (i.e., cellular respiration) require oxygen, just as a car engine needs oxygen to burn its fuel, and as a candle needs oxygen in order for its flame to burn.

Without oxygen, fuel cannot be processed to release energy.

You can read an overview of photosynthesis and the chemical reactions for photosynthesis and cellular respiration here:

http://www.bio.miami.edu/dana/dox/photosynthesis.html

I hope that will help explain the entire process, and why plants--like all living aerobic organisms--need oxygen to survive.  They need it to burn fuel for energy.  And they do use energy to grow and move and reproduce.  

Hope that helps!

Dana