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
Study shows how gene action may lead to diabetes prevention, cure
Dec 11, 2009 |
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A gene commonly studied by cancer researchers has been linked to the metabolic inflammation that leads to diabetes.
Study identifies genetic predeterminants for diabetes in African-Americans
Dec 09, 2009 |
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For years, scientists have tried to determine the basis for discrepancies between race and the predisposition for development of diseases such as type II diabetes and cardiovascular disease. Could factors ...
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Low-density lipoprotein receptor reduces damage in Alzheimer's brain
Medicine & Health / Neuroscience
Dec 09, 2009 |
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The low-density lipoprotein receptor (LDLR) has received a lot of attention because of its connection with coronary heart disease and atherosclerosis, but now it appears as if it may have a beneficial influence in degenerative ...
Study shows nearly 1/3 of human genome is involved in gingivitis
Dec 07, 2009 |
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Gingivitis, which may affect more than one-half of the U.S. adult population, is a condition commonly attributed to lapses in simple oral hygiene habits. However, a new study shows that development and reversal of gingivitis ...
Coffee Consumption Associated with Reduced Risk of Advanced Prostate Cancer
Dec 07, 2009 |
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(PhysOrg.com) -- While it is too early for physicians to start advising their male patients to take up the habit of regular coffee drinking, data presented at the American Association for Cancer Research Frontiers ...
UNC scientists coordinate study of link between insulin use and cancer in people with diabetes
47 minutes ago |
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Type 2 diabetes and obesity are linked to an increased risk of certain cancers. Recently published studies suggested that insulin glargine (a synthetic insulin preparation marketed under the trade name Lantus), ...
Researchers tackle protein mechanisms behind limb regeneration
3 hours ago |
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The most comprehensive study to date of the proteins in a species of salamander that can regrow appendages may provide important clues to how similar regeneration could be induced in humans.
Most Oncologists Feel New Genetic Test for Tamoxifen Sensitivity Not Ready for the Clinic
Dec 11, 2009 |
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(PhysOrg.com) -- Despite commercial availability and direct to consumer marketing of a new genetic test designed to reveal a breast cancer patient’s sensitivity to tamoxifen, most physicians in the U.S. are not currently ...
Parasite evades death by promoting host cell survival
Dec 08, 2009 |
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Researchers have discovered how the parasite Trypanosoma cruzi, which causes Chagas' disease, prolongs its survival in infected cells. A protein on the parasite activates the enzyme Akt, which blocks cell ...
'Extreme' genes shed light on origins of photosynthesis
Dec 11, 2009 |
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While most school children understand that green plants photosynthesize, absorb carbon dioxide and produce oxygen, few people consider the profound global-scale effects that photosynthesis has had on Earth. One of those actively ...
Fast, accurate urine test for pneumonia possible, study finds
Dec 09, 2009 |
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Doctors may soon be able to quickly and accurately diagnose the cause of pneumonia-like symptoms by examining the chemicals found in a patient's urine, suggests a new study led by UC Davis biochemist Carolyn ...
Transcription factors guide differences in human and chimp brain function
Dec 07, 2009 |
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Humans share at least 97 percent of their genes with chimpanzees, but, as a new study of transcription factors makes clear, what you have in your genome may be less important than how you use it.
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