- adenosine triphosphate
* * *▪ coenzyme(ATP),energy-carrying molecule found in the cells of all living things. ATP captures chemical energy obtained from the breakdown of food molecules and releases it to fuel other cellular processes.Cells require chemical energy for three general types of tasks: to drive metabolic reactions that would not occur automatically; to transport needed substances across membranes; and to do mechanical work, such as moving muscles. ATP is not a storage molecule for chemical energy; that is the job of carbohydrates, such as glycogen, and fats. When energy is needed by the cell, it is converted from storage molecules into ATP. ATP then serves as a shuttle, delivering energy to places within the cell where energy-consuming activities are taking place.ATP is a nucleotide that consists of three main structures: the nitrogenous base, adenine; the sugar, ribose; and a chain of three phosphate groups bound to ribose. The phosphate tail of ATP is the actual power source which the cell taps. Available energy is contained in the bonds between the phosphates and is released when they are broken, which occurs through the addition of a water molecule (a process called hydrolysis). Usually only the outer phosphate is removed from ATP to yield energy; when this occurs ATP is converted to adenosine diphosphate (ADP), the form of the nucleotide having only two phosphates.ATP is able to power cellular processes by transferring a phosphate group to another molecule (a process called phosphorylation). This transfer is carried out by special enzymes that couple the release of energy from ATP to cellular activities that require energy.Although cells continuously break down ATP to obtain energy, ATP also is constantly being synthesized from ADP and phosphate through the processes of cellular respiration. Most of the ATP in cells is produced by the enzyme ATP synthase, which converts ADP and phosphate to ATP. ATP synthase is located in the membrane of cellular structures called mitochondria; in plant cells, the enzyme also is found in chloroplasts. The central role of ATP in energy metabolism was discovered by Fritz Albert Lipmann and Herman Kalckar in 1941.
* * *
Look at other dictionaries:
Adenosine triphosphate — Adénosine triphosphate Pour les articles homonymes, voir ATP. Adénosine triphosphate … Wikipédia en Français
Adénosine-triphosphate — Pour les articles homonymes, voir ATP. Adénosine triphosphate … Wikipédia en Français
Adénosine Triphosphate — Pour les articles homonymes, voir ATP. Adénosine triphosphate … Wikipédia en Français
adénosine-triphosphate ou A.T.P. — ● adénosine triphosphate ou A.T.P. nom féminin Ester de l acide adénosine triphosphorique … Encyclopédie Universelle
adenosine triphosphate — adenosine triphosphate. См. АТФ. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
adenosine triphosphate — [trī fäs′fāt΄] n. ATP … English World dictionary
Adenosine triphosphate — For the Japanese rock band, see Adenosine Tri Phosphate (band). Adenosine triphosphate … Wikipedia
Adénosine triphosphate — Pour les articles homonymes, voir ATP. Adénosine triphosphate … Wikipédia en Français
adenosine triphosphate — ATP. A substance present in all living cells that provides energy for many metabolic processes and is involved in making RNA. Adenosine triphosphate made in the laboratory is being studied in patients with advanced solid tumors to see if it can… … English dictionary of cancer terms
adenosine triphosphate — adenosine 5 triphosphate Abbreviation: ATP A nucleotide of fundamental importance as the major carrier of chemical energy in all living organisms. It is also required for RNA synthesis since it is a direct precursor molecule. ATP consists of… … Glossary of Biotechnology
adenosine triphosphate — adenosine tri·phos·phate trī fäs .fāt n ATP * * * see ATP * * * (ATP) a nucleotide, the 5′ triphosphate of adenosine, involved in energy metabolism and required for RNA synthesis; it occurs in all cells and is used to store energy in the… … Medical dictionary