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
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News tagged with metabolism
Scientists find new link between insulin and core body temperature
Nov 19, 2009 |
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A team led by scientists at The Scripps Research Institute have discovered a direct link between insulin—a hormone long associated with metabolism and metabolic disorders such as diabetes—and core body temperature. While ...
Scientists find molecular trigger that helps prevent aging and disease
Nov 18, 2009 |
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Researchers at Mount Sinai School of Medicine set out to address a question that has been challenging scientists for years: How do dietary restriction—and the reverse, overconsumption—produce protective effects against aging ...
Extinct goat was cold-blooded
Nov 18, 2009 |
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(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.
Scientists pinpoint origin of dissolved arsenic in Bangladesh drinking water
Nov 15, 2009 |
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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 ...
Researchers discover mechanism of insulin production that can lead to better treatment for diabetes
Nov 12, 2009 |
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How a specific gene within the pancreas affects secretion of insulin has been discovered by researchers from the Hebrew University of Jerusalem, in collaboration with Japanese and American universities. Their ...
High fat diet increases inflammation in the mouse colon
Nov 12, 2009 |
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(PhysOrg.com) -- In mice fed a diet high in fat and low in fiber, vitamin D and calcium -- the so-called Western diet -- expression of a series of genes collectively associated with immune and inflammatory responses was altered. ...
Warm-blooded dinosaurs worked up a sweat
Nov 11, 2009 |
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(PhysOrg.com) -- Were dinosaurs endothermic (warm-blooded) like present-day mammals and birds or ectothermic (cold-blooded) like present-day lizards? The implications of this simple-sounding question go beyond ...
A 'spoonful of sugar' makes the worms' life span go down
Nov 03, 2009 |
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If worms are any indication, all the sugar in your diet could spell much more than obesity and type 2 diabetes. Researchers reporting in the November issue of Cell Metabolism, a Cell Press publication, say it might also b ...
Rice research gets a leg up on understanding plant reactions to environment
Nov 02, 2009 |
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One might say plants don't have a leg to stand on, but that may actually give them a leg up on the animal kingdom when it comes to environmental adaptability.
Slimming gene regulates body fat
Nov 02, 2009 |
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Scientists at the University of Bonn, Germany, have discovered a previously unknown fruit fly gene that controls the metabolism of fat. Larvae in which this gene is defective lose their entire fat reserves. Therefore the ...
Chewing gum can reduce calorie intake, increase energy expenditure
Oct 27, 2009 |
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A nutrition professor at the University of Rhode Island studying the effects of chewing sugar-free gum on weight management has found that it can help to reduce calorie intake and increase energy expenditure.
Protein critical for insulin secretion may be contributor to diabetes
Oct 26, 2009 |
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A cellular protein from a family involved in several human diseases is crucial for the proper production and release of insulin, new research has found, suggesting that the protein might play a role in diabetes.
Concurrent imaging of metabolic and electric signals in the heart
Oct 26, 2009 |
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Cardiac rhythm disorders can result from disturbances in cardiac metabolism. These metabolic changes are tightly linked with specific cardiac electrophysiology (CEP) abnormalities, such as depressed excitability, impaired ...
Scientists identify roots of diabetic tissue damage
Oct 22, 2009 |
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(PhysOrg.com) -- Results from comprehensive assessments of diabetes' effects on cell metabolism may aid efforts to reduce diabetic damage to nerves, blood vessels and other tissues, according to researchers at Washington ...
Study Shows How Normal Cells Influence Tumor Growth
Oct 21, 2009 |
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(PhysOrg.com) -- It was once thought that the two communities of cells within a cancerous breast tumor - fast-growing malignant cells and the normal cells that surround them - existed independently, without interaction. Then ...
