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
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 ...
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 ...
Dessert on your mind? Your muscles may be getting the message
Dec 01, 2009 |
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Even the anticipation of sweets may cause our muscles to start taking up more blood sugar, say researchers reporting in the December issue of Cell Metabolism. That message is delivered via neurons in the brain's hypothalamus contai ...
Western diets turn on fat genes
Nov 30, 2009 |
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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 ...
Research sheds light on workings of anti-cancer drug
Chemistry / Analytical Chemistry
Nov 26, 2009 |
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(PhysOrg.com) -- The copper sequestering drug tetrathiomolybdate (TM) has been shown in studies to be effective in the treatment of Wilson disease, a disease caused by an overload of copper, and certain metastatic cancers. ...
Upending textbook science on Alzheimer's disease
Medicine & Health / Neuroscience
Nov 23, 2009 |
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Alzheimer's disease is caused by the build-up of a brain peptide called amyloid-beta. That's why eliminating the protein has been the focus of almost all drug research pursuing a cure for the devastating neurodegenerative ...
Appetite, consumption controlled by clockwork genes at cross-purposes in flies
Dec 06, 2009 |
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One of the pioneers in research on sleep:wake circadian genes, Amita Sehgal, Ph.D., has discovered that fruit flies' appetite and consumption are controlled by two rival sets of clocks, one in neurons and the other in the ...
To keep muscles strong, the 'garbage' has to go
Dec 01, 2009 |
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In order to maintain muscle strength with age, cells must rid themselves of the garbage that accumulates in them over time, just as it does in any household, according to a new study in the December issue of Cell Metabolism. In the ...
Overeating can set stage for obesity, researchers say
Nov 27, 2009 |
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It doesn't seem like a fair fight. In one corner loomed the Thanksgiving table, groaning with poultry, pie and mashed potatoes.
Molecule discovered that makes obese people develop diabetes
Nov 24, 2009 |
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Many people who are overweight or obese develop insulin resistance and type 2 diabetes at some stage in their lives. A European research team has now discovered that obese people have large amounts of the ...
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 ...
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. ...
