Overview of Cellular Respiration in Plants
Cellular respiration in plants is the process by which cells break down glucose to produce energy in the form of ATP, essential for growth, reproduction, and maintenance. Unlike animals, plants perform respiration continuously, even during photosynthesis, but at a lower rate at night when light is absent. This process occurs in the mitochondria and is the counterpart to photosynthesis, which you learned about in the prerequisites.
Respiration can be summarized by the overall equation:
$$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP$$
Plants use oxygen absorbed through stomata or roots, and the process releases energy gradually through three main stages: glycolysis, the Krebs cycle (also called the citric acid cycle), and the electron transport chain (ETC). This breakdown provides up to 36-38 ATP molecules per glucose molecule, far more efficient than glycolysis alone.
Key point: Respiration occurs in all plant cells, supporting non-photosynthetic tissues like roots and flowers.