Difference between revisions of "Metabolism"
m (Text replacement - "http://" to "https://") |
|||
| Line 3: | Line 3: | ||
==Etymology== | ==Etymology== | ||
International Scientific Vocabulary, from [[Greek]] metabolē change, from metaballein to [[change]], from meta- + ballein to throw | International Scientific Vocabulary, from [[Greek]] metabolē change, from metaballein to [[change]], from meta- + ballein to throw | ||
| − | *Date: [ | + | *Date: [https://www.wikipedia.org/wiki/19th_Century 1878] |
==Definitions== | ==Definitions== | ||
*1 a : the sum of the [[processes]] in the buildup and destruction of [[protoplasm]]; specifically : the [[chemical]] [[changes]] in living [[cells]] by which [[energy]] is provided for [[vital]] processes and [[activities]] and new [[material]] is assimilated | *1 a : the sum of the [[processes]] in the buildup and destruction of [[protoplasm]]; specifically : the [[chemical]] [[changes]] in living [[cells]] by which [[energy]] is provided for [[vital]] processes and [[activities]] and new [[material]] is assimilated | ||
| Line 9: | Line 9: | ||
:c : the sum of the metabolic [[activities]] taking place in a particular [[environment]] <the metabolism of a lake> | :c : the sum of the metabolic [[activities]] taking place in a particular [[environment]] <the metabolism of a lake> | ||
==Description== | ==Description== | ||
| − | '''Metabolism''' is the set of [[chemical]] [[reactions]] that happen in living [[organisms]] to [[maintain]] life. These [[processes]] allow [[organisms]] to [[grow]] and [[reproduce]], maintain their [[structures]], and [[respond]] to their [[environments]]. Metabolism is usually divided into two categories. [ | + | '''Metabolism''' is the set of [[chemical]] [[reactions]] that happen in living [[organisms]] to [[maintain]] life. These [[processes]] allow [[organisms]] to [[grow]] and [[reproduce]], maintain their [[structures]], and [[respond]] to their [[environments]]. Metabolism is usually divided into two categories. [https://en.wikipedia.org/wiki/Catabolism Catabolism] breaks down [[organic]] [[matter]], for example to [[harvest]] [[energy]] in [[cellular]] [[respiration]]. [https://en.wikipedia.org/wiki/Anabolism Anabolism] uses [[energy]] to construct components of [[cells]] such as [https://en.wikipedia.org/wiki/Protein proteins] and [https://en.wikipedia.org/wiki/Nucleic_acid nucleic acids]. |
| − | The [[chemical]] [[reactions]] of metabolism are [[organized]] into metabolic pathways, in which one [[chemical]] is [[transformed]] through a [[series]] of steps into another [[chemical]], by a sequence of [ | + | The [[chemical]] [[reactions]] of metabolism are [[organized]] into metabolic pathways, in which one [[chemical]] is [[transformed]] through a [[series]] of steps into another [[chemical]], by a sequence of [https://en.wikipedia.org/wiki/Enzyme enzymes]. Enzymes are crucial to metabolism because they allow [[organisms]] to drive desirable [[reactions]] that require [[energy]] and will not occur by themselves, by coupling them to [[spontaneous]] reactions that release [[energy]]. As [https://en.wikipedia.org/wiki/Enzyme enzymes] [[act]] as [[catalysts]] they allow these [[reactions]] to proceed quickly and [[efficiently]]. Enzymes also allow the regulation of metabolic pathways in [[response]] to [[changes]] in the [[cell]]'s [[environment]] or signals from other cells. |
| − | The metabolism of an [[organism]] [[determines]] which substances it will find [[nutritious]] and which it will find [[poisonous]]. For example, some [ | + | The metabolism of an [[organism]] [[determines]] which substances it will find [[nutritious]] and which it will find [[poisonous]]. For example, some [https://en.wikipedia.org/wiki/Prokaryote prokaryotes] use [https://en.wikipedia.org/wiki/Hydrogen_sulfide hydrogen sulfide] as a nutrient, yet this [[gas]] is [[poisonous]] to [[animals]]. The [[speed]] of metabolism, the metabolic rate, also [[influences]] how much [[food]] an [[organism]] will require. |
| − | A striking feature of metabolism is the similarity of the basic metabolic pathways and components between even vastly [[different]] [[species]]. For example, the set of [ | + | A striking feature of metabolism is the similarity of the basic metabolic pathways and components between even vastly [[different]] [[species]]. For example, the set of [https://en.wikipedia.org/wiki/Carboxylic_acid carboxylic acids] that are best known as the [[intermediates]] in the [https://en.wikipedia.org/wiki/Citric_acid_cycle citric acid cycle] are present in all [[organisms]], being found in [[species]] as [[diverse]] as the unicellular bacteria [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] and huge multicellular organisms like [https://en.wikipedia.org/wiki/Elephant elephants]. These striking similarities in metabolism are probably due to the high efficiency of these pathways, and their early [[appearance]] in [[evolutionary]] [[history]]. |
[[Category: Chemistry]] | [[Category: Chemistry]] | ||
[[Category: Biology]] | [[Category: Biology]] | ||
Latest revision as of 01:28, 13 December 2020
Etymology
International Scientific Vocabulary, from Greek metabolē change, from metaballein to change, from meta- + ballein to throw
- Date: 1878
Definitions
- 1 a : the sum of the processes in the buildup and destruction of protoplasm; specifically : the chemical changes in living cells by which energy is provided for vital processes and activities and new material is assimilated
- b : the sum of the processes by which a particular substance is handled in the living body
- c : the sum of the metabolic activities taking place in a particular environment <the metabolism of a lake>
Description
Metabolism is the set of chemical reactions that happen in living organisms to maintain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories. Catabolism breaks down organic matter, for example to harvest energy in cellular respiration. Anabolism uses energy to construct components of cells such as proteins and nucleic acids.
The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical, by a sequence of enzymes. Enzymes are crucial to metabolism because they allow organisms to drive desirable reactions that require energy and will not occur by themselves, by coupling them to spontaneous reactions that release energy. As enzymes act as catalysts they allow these reactions to proceed quickly and efficiently. Enzymes also allow the regulation of metabolic pathways in response to changes in the cell's environment or signals from other cells.
The metabolism of an organism determines which substances it will find nutritious and which it will find poisonous. For example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals. The speed of metabolism, the metabolic rate, also influences how much food an organism will require.
A striking feature of metabolism is the similarity of the basic metabolic pathways and components between even vastly different species. For example, the set of carboxylic acids that are best known as the intermediates in the citric acid cycle are present in all organisms, being found in species as diverse as the unicellular bacteria Escherichia coli and huge multicellular organisms like elephants. These striking similarities in metabolism are probably due to the high efficiency of these pathways, and their early appearance in evolutionary history.
