Metabolism
hideMetabolism is the set of chemical reactions that occur 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, on the other hand, 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 into another by a sequence of enzymes. Enzymes are crucial to metabolism because they allow organisms to drive desirable but thermodynamically unfavorable reactions by coupling them to favorable ones, and because they act as catalysts to 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 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 most likely the result of the high efficiency of these pathways, and of their early appearance in evolutionary history.
For more information about Metabolism, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with metabolism
Extinct goat was cold-blooded
Nov 18, 2009 |
4.9 / 5 (39) |
12
(PhysOrg.com) -- An extinct goat that lived on a barren Mediterranean island survived for millions of years by reducing in size and by becoming cold-blooded, which has never before been discovered in mammals.
Exotic life beyond Earth? Looking for life as we don't know it
Space & Earth / Space Exploration
Sep 18, 2009 |
4.8 / 5 (24) |
8
Scientists at a new interdisciplinary research institute in Austria are working to uncover how life might evolve with "exotic" biochemistry and solvents, such as sulphuric acid instead of water. Their research ...
Scientists pinpoint origin of dissolved arsenic in Bangladesh drinking water
Nov 15, 2009 |
4.8 / 5 (21) |
1
Researchers in MIT's Department of Civil and Environmental Engineering believe they have pinpointed a pathway by which arsenic may be contaminating the drinking water in Bangladesh, a phenomenon that has puzzled ...
Disabling enzyme allows mice to gorge without becoming obese, new study finds
Jan 11, 2009 |
5 / 5 (13) |
1
Researchers at the University of California, Berkeley, have identified a new enzyme that plays a far more important role than expected in controlling the breakdown of fat. In a new study to be published Jan. 11 in the journal ...
Nearly a century later, new findings support Warburg theory of cancer
Jan 12, 2009 |
4.9 / 5 (12) |
1
German scientist Otto H. Warburg's theory on the origin of cancer earned him the Nobel Prize in 1931, but the biochemical basis for his theory remained elusive.
Exercise could be the heart's fountain of youth
Jul 23, 2008 |
4.3 / 5 (11) |
0
Absence may make the heart grow fonder, but endurance exercise seems to make it younger. According to a study conducted at Washington University School of Medicine in St. Louis, older people who did endurance exercise training ...
How cigarettes calm you down
Apr 24, 2009 |
4.8 / 5 (9) |
0
The calming neurological effects of nicotine have been demonstrated in a group of non-smokers during anger provocation. Researchers writing in BioMed Central's open access journal Behavioral and Brain Functions suggest that n ...
Key protein may explain the anti-aging and anti-cancer benefits of dietary restriction
May 22, 2009 |
4.7 / 5 (9) |
3
A protein that plays a key role in tumor formation, oxygen metabolism and inflammation is involved in a pathway that extends lifespan by dietary restriction. The finding, which appears in the May 22, 2009 edition of the ...
Scientists a step closer to producing fuel from bacteria
Biology /
Aug 06, 2008 |
3.4 / 5 (12) |
1
Scientists at the University of Sheffield have shown how bacteria could be used as a future fuel. The research, published in the journal Bioinformatics, could have significant implications for the environment and the way we ...
Vitamin D may exacerbate autoimmune disease
Apr 08, 2009 |
4.1 / 5 (9) |
4
Deficiency in vitamin D has been widely regarded as contributing to autoimmune disease, but a review appearing in Autoimmunity Reviews explains that low levels of vitamin D in patients with autoimmune disease may be a resu ...
Looking for signs of early life
Space & Earth / Earth Sciences
Jul 08, 2009 |
4 / 5 (9) |
0
(PhysOrg.com) -- Deciphering the very early history of life on Earth is difficult. In the darkest recesses of the first billion years there are no 'body' fossils - no physical remains. Instead, scientists ...
Could Dr. House be replaced by a computer?
Oct 16, 2008 |
4.7 / 5 (7) |
1
Scientists know that different normal and diseased tissues behave differently. But a method that tells them just how they do so may one day give medical science a new way to fight obesity, hypertension, diabetes and other ...
Study finds citrus-derived flavonoid prevents obesity
Jul 13, 2009 |
4.7 / 5 (7) |
0
(PhysOrg.com) -- A flavonoid derived from citrus fruit has shown tremendous promise for preventing weight gain and other signs of metabolic syndrome which can lead to Type 2 Diabetes and increased risk of cardiovascular disease. ...
Western diets turn on fat genes
Nov 30, 2009 |
4.7 / 5 (7) |
1
Those extra helpings of gravy and dessert at the holiday table are even less of a help to your waistline than previously thought. According to a new research report recently appearing online in The FASEB Journal, a diet t ...
New clues to pancreatic cells' destruction in diabetes
Biology /
Feb 03, 2009 |
5 / 5 (6) |
0
Researchers have found what appears to be a major culprit behind the loss of insulin-producing β cells from the pancreases of people with diabetes, a critical event in the progression of the disease.
