Catabolism: Difference between revisions
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[[Image:Catabolism schematic.svg|thumb|250px|right|Schematical diagram]] |
[[Image:Catabolism schematic.svg|thumb|250px|right|Schematical diagram]] |
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'''Catabolism''' (from [[Ancient Greek|Greek]] κάτω ''kato'', "downward" and βάλλειν ''ballein'', "to throw") is the set of [[Metabolism|metabolic]] pathways that breaks down [[molecule]]s into smaller units that are either oxidized to release [[energy]], or used in other [[anabolic]] reactions.<ref>{{cite web |url=http://www.chem.qmul.ac.uk/iupac/bioinorg/CD.html#8 |title=Glossary of Terms Used in Bioinorganic Chemistry: Catabolism |accessdate=2007-10-30 |last=de Bolster |first=M.W.G. |year=1997 |publisher=International Union of Pure and Applied Chemistry}}</ref> Catabolism breaks down large molecules (such as [[polysaccharide]]s, [[lipid]]s, [[nucleic acid]]s and [[protein]]s) into smaller units (such as [[monosaccharide]]s, [[fatty acid]]s, [[nucleotide]]s, and [[amino acid]]s, respectively). The pathways for catabolism and anabolism use different enzymes but are regulated by the same molecules, so they take place in different locations and |
'''Catabolism''' (from [[Ancient Greek|Greek]] κάτω ''kato'', "downward" and βάλλειν ''ballein'', "to throw") is the set of [[Metabolism|metabolic]] pathways that breaks down [[molecule]]s into smaller units that are either oxidized to release [[energy]], or used in other [[anabolic]] reactions.<ref>{{cite web |url=http://www.chem.qmul.ac.uk/iupac/bioinorg/CD.html#8 |title=Glossary of Terms Used in Bioinorganic Chemistry: Catabolism |accessdate=2007-10-30 |last=de Bolster |first=M.W.G. |year=1997 |publisher=International Union of Pure and Applied Chemistry}}</ref> Catabolism breaks down large molecules (such as [[polysaccharide]]s, [[lipid]]s, [[nucleic acid]]s and [[protein]]s) into smaller units (such as [[monosaccharide]]s, [[fatty acid]]s, [[nucleotide]]s, and [[amino acid]]s, respectively). The pathways for catabolism and anabolism use different enzymes but are regulated by the same molecules, so they take place in different locations and [[organelle]]s in cells to avoid interfering with one another.<ref>{{cite web|title=Catabolism|url=https://biologydictionary.net/catabolism|website=biologydictionary.net|accessdate=31 July 2017}}</ref> |
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Cells use the monomers released from breaking down polymers to either construct new polymer molecules, or degrade the monomers further to simple waste products, releasing energy. Cellular wastes include [[lactic acid]], [[acetic acid]], [[carbon dioxide]], [[ammonia]], and [[urea]]. The creation of these wastes is usually an [[oxidation]] process involving a release of chemical free energy, some of which is lost as [[heat]], but the rest of which is used to drive the synthesis of [[adenosine triphosphate]] (ATP). This molecule acts as a way for the cell to transfer the energy released by catabolism to the energy-requiring reactions that make up [[anabolism]]. (Catabolism is seen as destructive [[metabolism]] and anabolism as constructive metabolism). Catabolism therefore provides the chemical energy necessary for the maintenance and growth of cells. Examples of catabolic processes include [[glycolysis]], the [[citric acid cycle]], the breakdown of muscle protein in order to use amino acids as [[substrate (biochemistry)|substrate]]s for [[gluconeogenesis]], the breakdown of [[fat]] in [[adipose tissue]] to [[fatty acid]]s, and [[oxidative deamination]] of neurotransmitters by [[monoamine oxidase]]. |
Cells use the monomers released from breaking down polymers to either construct new polymer molecules, or degrade the monomers further to simple waste products, releasing energy. Cellular wastes include [[lactic acid]], [[acetic acid]], [[carbon dioxide]], [[ammonia]], and [[urea]]. The creation of these wastes is usually an [[oxidation]] process involving a release of chemical free energy, some of which is lost as [[heat]], but the rest of which is used to drive the synthesis of [[adenosine triphosphate]] (ATP). This molecule acts as a way for the cell to transfer the energy released by catabolism to the energy-requiring reactions that make up [[anabolism]]. (Catabolism is seen as destructive [[metabolism]] and anabolism as constructive metabolism). Catabolism therefore provides the chemical energy necessary for the maintenance and growth of cells. Examples of catabolic processes include [[glycolysis]], the [[citric acid cycle]], the breakdown of muscle protein in order to use amino acids as [[substrate (biochemistry)|substrate]]s for [[gluconeogenesis]], the breakdown of [[fat]] in [[adipose tissue]] to [[fatty acid]]s, and [[oxidative deamination]] of neurotransmitters by [[monoamine oxidase]]. |
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There are many signals that control catabolism. Most of the known signals are [[hormone]]s and the molecules involved in metabolism itself. [[Endocrinologist]]s have traditionally classified many of the hormones as [[anabolic]] or catabolic, depending on which part of metabolism they stimulate. The so-called classic catabolic hormones known since the early 20th century are [[cortisol]], [[glucagon]], and [[adrenaline]] (and other [[catecholamine]]s). In recent decades, many more hormones with at least some catabolic effects have been discovered, including [[cytokine]]s, [[orexin]] (also known as [[hypocretin]]), and [[melatonin]].{{Citation needed|date=April 2010}} |
There are many signals that control catabolism. Most of the known signals are [[hormone]]s and the molecules involved in metabolism itself. [[Endocrinologist]]s have traditionally classified many of the hormones as [[anabolic]] or catabolic, depending on which part of metabolism they stimulate. The so-called classic catabolic hormones known since the early 20th century are [[cortisol]], [[glucagon]], and [[adrenaline]] (and other [[catecholamine]]s). In recent decades, many more hormones with at least some catabolic effects have been discovered, including [[cytokine]]s, [[orexin]] (also known as [[hypocretin]]), and [[melatonin]].{{Citation needed|date=April 2010}} |
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Many of these catabolic hormones express an anti-catabolic effect in muscle tissue. One study found that the administration of [[ |
Many of these catabolic hormones express an anti-catabolic effect in muscle tissue. One study found that the administration of [[adrenaline]] had an anti-proteolytic effect, and in fact suppressed catabolism rather than promoted it.<ref>{{cite journal |pmid=7840182 |url=http://ajpendo.physiology.org/cgi/pmidlookup?view=reprint&pmid=7840182 |journal=American Journal of Physiology. Endocrinology and Metabolism |title=Effects of epinephrine on human muscle glucose and protein metabolism |year=1995 |first1=DA |last1=Fryburg |volume=268 |issue=1 |pages=E55–9 |last2=Gelfand |first2=RA |last3=Jahn |first3=LA |last4=Oliveras |first4=D |last5=Sherwin |first5=RS |last6=Sacca |first6=L |last7=Barrett |first7=EJ}}</ref> Another study found that catecholamines in general (the main ones being, epinephrine, [[norepinephrine]] and [[dopamine]]), greatly decreased the rate of muscle catabolism.<ref> |
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{{cite journal |pmid=11500299 |url=http://ajpendo.physiology.org/cgi/pmidlookup?view=long&pmid=11500299 |
{{cite journal |pmid=11500299 |url=http://ajpendo.physiology.org/cgi/pmidlookup?view=long&pmid=11500299 |
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|title=Catecholamines inhibit Ca<sup>2+</sup>-dependent proteolysis in rat skeletal muscle through β<sub>2</sub>-adrenoceptors and cAMP |first1=Luiz Carlos C. |last1=Navegantes |first2=Neusa M. Z. |last2=Resano |first3=Renato H. |last3=Migliorini |first4=Ísis C. |last4=Kettelhut |journal=American Journal of Physiology. Endocrinology and Metabolism |year=2001 |volume=281 |issue=3 |pages=E449–54 |
|title=Catecholamines inhibit Ca<sup>2+</sup>-dependent proteolysis in rat skeletal muscle through β<sub>2</sub>-adrenoceptors and cAMP |first1=Luiz Carlos C. |last1=Navegantes |first2=Neusa M. Z. |last2=Resano |first3=Renato H. |last3=Migliorini |first4=Ísis C. |last4=Kettelhut |journal=American Journal of Physiology. Endocrinology and Metabolism |year=2001 |volume=281 |issue=3 |pages=E449–54 |
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Revision as of 09:42, 23 November 2017
Catabolism (from Greek κάτω kato, "downward" and βάλλειν ballein, "to throw") is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy, or used in other anabolic reactions.[1] Catabolism breaks down large molecules (such as polysaccharides, lipids, nucleic acids and proteins) into smaller units (such as monosaccharides, fatty acids, nucleotides, and amino acids, respectively). The pathways for catabolism and anabolism use different enzymes but are regulated by the same molecules, so they take place in different locations and organelles in cells to avoid interfering with one another.[2]
Cells use the monomers released from breaking down polymers to either construct new polymer molecules, or degrade the monomers further to simple waste products, releasing energy. Cellular wastes include lactic acid, acetic acid, carbon dioxide, ammonia, and urea. The creation of these wastes is usually an oxidation process involving a release of chemical free energy, some of which is lost as heat, but the rest of which is used to drive the synthesis of adenosine triphosphate (ATP). This molecule acts as a way for the cell to transfer the energy released by catabolism to the energy-requiring reactions that make up anabolism. (Catabolism is seen as destructive metabolism and anabolism as constructive metabolism). Catabolism therefore provides the chemical energy necessary for the maintenance and growth of cells. Examples of catabolic processes include glycolysis, the citric acid cycle, the breakdown of muscle protein in order to use amino acids as substrates for gluconeogenesis, the breakdown of fat in adipose tissue to fatty acids, and oxidative deamination of neurotransmitters by monoamine oxidase.
There are many signals that control catabolism. Most of the known signals are hormones and the molecules involved in metabolism itself. Endocrinologists have traditionally classified many of the hormones as anabolic or catabolic, depending on which part of metabolism they stimulate. The so-called classic catabolic hormones known since the early 20th century are cortisol, glucagon, and adrenaline (and other catecholamines). In recent decades, many more hormones with at least some catabolic effects have been discovered, including cytokines, orexin (also known as hypocretin), and melatonin.[citation needed]
Many of these catabolic hormones express an anti-catabolic effect in muscle tissue. One study found that the administration of adrenaline had an anti-proteolytic effect, and in fact suppressed catabolism rather than promoted it.[3] Another study found that catecholamines in general (the main ones being, epinephrine, norepinephrine and dopamine), greatly decreased the rate of muscle catabolism.[4]
See also
- Autophagy
- Dehydration synthesis
- Hydrolysis
- Nocturnal post absorptive catabolism
- Psilacetin § Pharmacology
- Sarcopenia
References
- ^ de Bolster, M.W.G. (1997). "Glossary of Terms Used in Bioinorganic Chemistry: Catabolism". International Union of Pure and Applied Chemistry. Retrieved 2007-10-30.
- ^ "Catabolism". biologydictionary.net. Retrieved 31 July 2017.
- ^ Fryburg, DA; Gelfand, RA; Jahn, LA; Oliveras, D; Sherwin, RS; Sacca, L; Barrett, EJ (1995). "Effects of epinephrine on human muscle glucose and protein metabolism". American Journal of Physiology. Endocrinology and Metabolism. 268 (1): E55–9. PMID 7840182.
- ^ Navegantes, Luiz Carlos C.; Resano, Neusa M. Z.; Migliorini, Renato H.; Kettelhut, Ísis C. (2001). "Catecholamines inhibit Ca2+-dependent proteolysis in rat skeletal muscle through β2-adrenoceptors and cAMP". American Journal of Physiology. Endocrinology and Metabolism. 281 (3): E449–54. PMID 11500299.
External links
Media related to Catabolism at Wikimedia Commons
