Animals store the energy obtained from the breakdown of food as ATP. Likewise, plants capture and store the energy they derive from light during photosynthesis in ATP molecules. ATP is a nucleotide consisting of an adenine base attached to a ribose sugar, which is attached to three phosphate groups. These three phosphate groups are linked to one another by two high-energy bonds called phosphoanhydride bonds.
When one phosphate group is removed by breaking a phosphoanhydride bond in a process called hydrolysis, energy is released, and ATP is converted to adenosine diphosphate ADP. Chemiosmosis involves the creation of a steep proton hydrogen ion gradient. This gradient occurs between the membrane-bound compartments of the mitochondria of all cells and the chloroplasts of plant cells. A gradient is formed when large numbers of protons hydrogen ions are pumped into the membrane-bound compartments of the mitochondria.
The protons build up dramatically within the compartment, finally reaching an enormous number. The energy released from the electrons during the electron transport system pumps the protons.
After large numbers of protons have gathered within the compartments of mitochondria and chloroplasts, they suddenly reverse their directions and escape back across the membranes and out of the compartments. The escaping protons release their energy in this motion. The energy is trapped in the high-energy bond of ATP by this process, and the ATP molecules are made available to perform cell work. The movement of protons is chemiosmosis because it is a movement of chemicals in this case, protons across a semipermeable membrane.
ATP is biosynthesized in several ways, as described by Biology Dictionary :. Photophosphorylation is a method specific to plants and cyanobacteria. ATP is also formed from the process of cellular respiration in the mitochondria of a cell.
This can be through aerobic respiration, which requires oxygen, or anaerobic respiration, which does not. Aerobic respiration produces ATP along with carbon dioxide and water from glucose and oxygen. Anaerobic respiration uses chemicals other than oxygen, and this process is primarily used by archaea and bacteria that live in anaerobic environments.
Fermentation is another way of producing ATP that does not require oxygen; it is different from anaerobic respiration because it does not use an electron transport chain. Yeast and bacteria are examples of organisms that use fermentation to generate ATP. ATP synthesized in mitochondria is the primary energy source for important biological functions, such as muscle contraction, nerve impulse transmission, and protein synthesis. This molecule was suggested by a reader.
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