Why do plants require oxygen as well as carbon dioxide?

Question

Why do plants require oxygen as well as carbon dioxide?

Answer 1

Plants have mitochondria as well, like us animals do. The only difference is that they can fix CO2 into organic carbon and eventually glucose, for use and storage. To break down this glucose, it undergoes the same process that happens in our body. Glycolysis occurs in the cytoplasm, and then pyruvate is sent to the Krebs cycle.

As the Krebs cycle does its thing, electrons are passed down the electron transport chain. The electrons eventually end up at the most electronegative molecule: Oxygen. Then the oxygen picks up a couple of H+ ions, and forms water. So as you can see, plants, just like us, need oxygen to break down their food they create.

Answer 2

Well, when it's germinating under the soil, it needs 3 things: warmth, water and oxygen. It already has a food store inside it, so I guess it doesn't need carbon-dioxide, but oxygen makes the chemicals react in it or something. Then when it grows its leaves, it uses carbon-dioxide to make food.

Answer 3

Water logged soil will quickly cause a plant to die due to lack of oxygen.  The oxygen is used in cellular respiration to produce energy needed for cellular metabolism.  Plants photosynthesize only when there is sufficient light.  They need energy in the form of ATP all the time.  So cellular respiration is 100 % of the time.