Faculty resources from Thomas Nelson Community College explain that cellular respiration is the process by which cells produce adenosine triphosphate, or ATP. ATP is the molecule that carries energy for the cells of an organism, and it functions as a “currency” for the cells in an organism. Cells cannot store ATP; instead, they must produce it continuously or the organism will die.
Cellular respiration is usually divided into three distinct parts, according to the resources from Thomas Nelson Community College. The first part of cellular respiration is called glycolysis, in which glucose is broken into pieces called pyruvate. Next, the Kreb’s cycle breaks down the carbon bonds and produces the waste gas that animals exhale, carbon dioxide. The final step in the cycle is called electron transport and oxidative phosphorylation. Though not necessary for the first two steps, in this part of the process, oxygen is necessary and used to produce ATP.
Cells primarily engage in cellular respiration in small organelles called mitochondria. Mitochondria are the energy producers of the cell. To engage in the process of cellular respiration, mitochondria require a supply of oxygen. According to Thomas Nelson Community College, all eukaryotes, including plants, require oxygen. Other energy-producing pathways exist besides cellular respiration, including fermentation and anaerobic metabolism.