ATP: Difference between revisions
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=== In general === | === In general === | ||
ATP ([[Adenosine|adenosine]] triphosphate) is a high energy molecule that is [[Hydrolysed|hydrolysed]] to provide energy for many reactions within the mammalian body. ATP is mainly synthesised in the [[Mitochondria|mitochondria]] of a [[Cell|cell]], in a process called [[Oxidative phosphorylation|oxidative phosphorylation]], via [[Electron transfer chain|electron transfer chain]]. A small amount of ATP is synthesised in the [[Cytoplasm|cytoplasm]] during [[Glycolysis|glycolysis]]. ATP is a very important source of energy for many cellular functions, including in [[Muscle|muscle]] contraction, [[Active transport|active transport]] and [[Condensation Reaction|condensation reactions]]. The [[Molecular|molecular]] structure of ATP constists of three [[Phosphate|phosphate]] groups linked to an [[Adenosine|adenosine]] core. These [[Phosphate group|phosphate groups]] are linked in series by two [[Phosphoanhydride bond|phosphoanhydride bonds]] <ref>Molecular Biology of the Cell,5th Edition, 2008 Alberts et al., page 61</ref>.<br> | ATP ([[Adenosine|adenosine]] triphosphate) is a high energy molecule that is [[Hydrolysed|hydrolysed]] to provide energy for many reactions within the mammalian body. ATP is mainly synthesised in the [[Mitochondria|mitochondria]] of a [[Cell|cell]], in a process called [[Oxidative phosphorylation|oxidative phosphorylation]], via [[Electron transfer chain|electron transfer chain]]. A small amount of ATP is synthesised in the [[Cytoplasm|cytoplasm]] during [[Glycolysis|glycolysis]], and during the Krebs cycle in the [[mitochondria|Mitochondria]]. ATP is a very important source of energy for many cellular functions, including in [[Muscle|muscle]] contraction, [[Active transport|active transport]] and [[Condensation Reaction|condensation reactions]]. The [[Molecular|molecular]] structure of ATP constists of three [[Phosphate|phosphate]] groups linked to an [[Adenosine|adenosine]] core. These [[Phosphate group|phosphate groups]] are linked in series by two [[Phosphoanhydride bond|phosphoanhydride bonds]] <ref>Molecular Biology of the Cell,5th Edition, 2008 Alberts et al., page 61</ref>.<br> | ||
=== Formation during respiration === | |||
<ref>Books, C. and Books, C (2009) A2-level Biology AQA Revision, United Kingdom: Coordination Group publications LTD. Pages 22-25</ref> | |||
=== ATP Hydrolysis === | === ATP Hydrolysis === | ||
[[Hydrolysis|Hydrolysing]] ATP to [http://en.wikipedia.org/wiki/Adenosine_diphosphate ADP (adenosine diphosphate)] or further to [[AMP|AMP]] ([[AMP|adenosine monophosphate]]) releases a large amount of [http://en.wikipedia.org/wiki/Thermodynamic_free_energy free energy], because the [[Phosphoanhydride bonds|phosphoanhydride bonds]] in the [[Molecule|molecule]] are broken <ref>Stryer et al. 2006, Biochemistry, 5th edition, W.H. Freeman and Company, New York.</ref>. ATP is, however, a very stable [[Molecule|molecule]] and will only release its energy in the presence of [[ATPase|ATPase]].<br> | [[Hydrolysis|Hydrolysing]] ATP to [http://en.wikipedia.org/wiki/Adenosine_diphosphate ADP (adenosine diphosphate)] or further to [[AMP|AMP]] ([[AMP|adenosine monophosphate]]) releases a large amount of [http://en.wikipedia.org/wiki/Thermodynamic_free_energy free energy], because the [[Phosphoanhydride bonds|phosphoanhydride bonds]] in the [[Molecule|molecule]] are broken <ref>Stryer et al. 2006, Biochemistry, 5th edition, W.H. Freeman and Company, New York.</ref>. ATP is, however, a very stable [[Molecule|molecule]] and will only release its energy in the presence of [[ATPase|ATPase]].<br> | ||
=== '''ATP Cycle''' === | === '''ATP Cycle''' === | ||
Revision as of 12:06, 28 November 2014
| Adenosine Triphosphate |
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| Adenine base (Red), Ribose (Pink), Phosphate (Blue) [1] |
In general
ATP (adenosine triphosphate) is a high energy molecule that is hydrolysed to provide energy for many reactions within the mammalian body. ATP is mainly synthesised in the mitochondria of a cell, in a process called oxidative phosphorylation, via electron transfer chain. A small amount of ATP is synthesised in the cytoplasm during glycolysis, and during the Krebs cycle in the Mitochondria. ATP is a very important source of energy for many cellular functions, including in muscle contraction, active transport and condensation reactions. The molecular structure of ATP constists of three phosphate groups linked to an adenosine core. These phosphate groups are linked in series by two phosphoanhydride bonds [2].
Formation during respiration
ATP Hydrolysis
Hydrolysing ATP to ADP (adenosine diphosphate) or further to AMP (adenosine monophosphate) releases a large amount of free energy, because the phosphoanhydride bonds in the molecule are broken [4]. ATP is, however, a very stable molecule and will only release its energy in the presence of ATPase.
ATP Cycle
ATP ↔ ADP +Pi
Formation of ATP requires energy input, therefore it must be coupled to energy-generating processes, such as photosynthesis or oxidation of food molecules. Hydrolysis of ATP releases a lot of free energy, therefore it must be coupled to energy-requiring processes such as muscle contraction and active transport.[5]
What makes ATP an efficient energy source
ATP is the most common energy source in most cellular metabolism. However, some other cellular metabolism were not driven by ATP. Such an example of the other energy currency used in cellular metabolism is guanosine triphosphate (GTP), uridine triphosphate (UTP), and Cytidine triphosphate (CTD). Nonetheless, ATP is the most efficient energy source used in cellular metabolism. The reasons that ATP is more reliable than the other nucleoside triphosphate in producing energy are:
- ATP have an unstable structure compared to ADP. Thus, ATP has a high phosphoryl-transfer potential (tendency to release phosphate to become ADP is high) [6]
- At neutral pH, triphosphate of ATP have a great repulsion between each other. This is because, at pH 7, all the phosphate of ATP carries a negative charge. The electrostatic repulsion causes the phosphate group to be easily released [7].
References
- ↑ http://www.chm.bris.ac.uk/motm/atp/atp_text.htm
- ↑ Molecular Biology of the Cell,5th Edition, 2008 Alberts et al., page 61
- ↑ Books, C. and Books, C (2009) A2-level Biology AQA Revision, United Kingdom: Coordination Group publications LTD. Pages 22-25
- ↑ Stryer et al. 2006, Biochemistry, 5th edition, W.H. Freeman and Company, New York.
- ↑ Lodish H, Berk A, Zipursky SL, et al. Molecular Cell Biology. 4th edition. New York: W. H. Freeman; 2000. Section 2.4, Biochemical Energetics. [Online} Available from: http://www.ncbi.nlm.nih.gov/books/NBK21737/ [Accessed:25/11/2014]
- ↑ Berg, J.M., Tymoczko, J.L., Stryer, L. and Gatto, G.J., 2010. Biochemistry. 7th ed. England: W.H. Freeman and Company.
- ↑ Berg, J.M., Tymoczko, J.L., Stryer, L. and Gatto, G.J., 2010. Biochemistry. 7th ed. England: W.H. Freeman and Company.