Carbohydrate metabolism
hideCarbohydrate metabolism denotes the various biochemical processes responsible for the formation, breakdown and interconversion of carbohydrates in living organisms.
The most important carbohydrate is glucose, a simple sugar (monosaccharide) that is metabolized by nearly all known organisms. Glucose and other carbohydrates are part of a wide variety of metabolic pathways across species: plants synthesize carbohydrates from atmospheric gases by photosynthesis storing the absorbed energy internally, often in the form of starch or lipids. Plant components are eaten by animals and fungi, and used as fuel for cellular respiration. Oxidation of one gram of carbohydrate yields approximately 4 kcal of energy and from lipids about 9 kcal. Energy obtained from metabolism (eg, oxidation of glucose) is usually stored temporarily within cells in the form of ATP. Organisms capable of aerobic respiration metabolize glucose and oxygen to release energy with carbon dioxide and water as byproducts.
Carbohydrates are a superior short-term fuel for organisms because they are simpler to metabolize than fats or those amino acid portions of proteins that are used for fuel. In animals, the most important carbohydrate is glucose; so much so, that the level of glucose is used as the main control for the central metabolic hormone, insulin. Starch, and cellulose in a few organisms (eg, termites, ruminants, and some bacteria), being both glucose polymers are disassembled during digestion and absorbed as glucose. Some simple carbohydrates have their own enzymatic oxidation pathways, as do only a few of the more complex carbohydrates. The disaccharide lactose, for instance, requires the enzyme lactase to be broken into into its monosaccharides components; many animals lack this enzyme in adulthood.
Carbohydrates are typically stored as long polymers of glucose molecules with Glycosidic bonds for structural support (e.g. chitin, cellulose) or for energy storage (e.g. glycogen, starch). However, the strong affinity of most carbohydrates for water makes storage of large quantities of carbohydrates inefficient due to the large molecular weight of the solvated water-carbohydrate complex. In most organisms, excess carbohydrates are regularly catabolised to form Acetyl-CoA, which is a feed stock for the fatty acid synthesis pathway; fatty acids, triglycerides, and other lipids are commonly used for long-term energy storage. The hydrophobic character of lipids makes them a much more compact form of energy storage than hydrophilic carbohydrates. However, animals, including humans, lack the necessary enzymatic machinery and so do not synthesize glucose from lipids. <ref, G Cooper, The Cell, American Society of Microbiology, p 72>
All carbohydrates share a general formula of approximately CnH2nOn; glucose is C6H12O6. Monosaccharides may be chemically bonded together to form disaccharides such as sucrose and longer polysaccharides such as starch and cellulose.
For more information about Carbohydrate 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 glucose metabolism
Scientists find molecular trigger that helps prevent aging and disease
Nov 18, 2009 |
not rated yet |
0
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 ...
Future diabetes treatment may use resveratrol to target the brain
Oct 06, 2009 |
5 / 5 (2) |
0
Resveratrol, a molecule found in red grapes, has been shown to improve diabetes when delivered orally to rodents. Until now, however, little has been known about how these beneficial changes are mediated in the body. A new ...
Scientists identify gene that predicts post-surgical survival from brain metastasis of breast cancer patients
Sep 01, 2009 |
5 / 5 (3) |
0
Researchers at the National Cancer Institute have identified a gene that may play a role in breast cancer metastasis to the brain, according to a report in Molecular Cancer Research, a journal of the Americ ...
Researchers evaluate resistance training for diabetes prevention
Aug 25, 2009 |
5 / 5 (1) |
0
Systematic, progressive resistance training - also called strength training - is a safe and efficient way for middle-aged and older adults to improve their health. A Virginia Tech led research team that includes ...
Peptide linked to glucose metabolism and neuronal cell survival (w/ Video)
Jul 22, 2009 |
5 / 5 (5) |
0
A cellular protein that may prevent nerve cells from dying also helps to improve insulin action and lower blood glucose levels, according to a study by researchers at Albert Einstein College of Medicine of ...
Researchers find early markers of Alzheimer's disease
Jul 14, 2009 |
1 / 5 (1) |
0
A large study of patients with mild cognitive impairment revealed that results from cognitive tests and brain scans can work as an early warning system for the subsequent development of Alzheimer's disease.
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. ...
'Jumping gene' diminishes the effect of a new type 2 diabetes risk gene
Jul 03, 2009 |
5 / 5 (1) |
0
Research led by the German Institute of Human Nutrition (DIfE) has identified a new gene associated with diabetes, together with a mechanism that makes obese mice less susceptible to diabetes.
Hungry cells
Jun 16, 2009 |
not rated yet |
1
People who suffer from Peutz-Jeghers syndrome, a rare inherited cancer syndrome, develop gastrointestinal polyps and are predisposed to colon cancer and other tumor types. Carefully tracing the cellular chain-of-command ...
Researchers discover new glucose-regulating protein linked with diabetes
May 28, 2009 |
5 / 5 (1) |
0
Researchers at the University of California, San Francisco, and collaborators at Harvard Medical School have linked a specialized protein in human muscles to the process that clears glucose out of the bloodstream, shedding ...
Heart disease patients carrying extra pounds do better, live longer
May 18, 2009 |
not rated yet |
0
Being overweight or obese is a leading contributor to cardiovascular disease (CVD) and associated risk factors; however, in patients with established CVD, obesity appears to play a protective role. In fact, data suggest obese ...
Humanin peptide linked to neuronal cell survival and regulation of glucose metabolism
Apr 22, 2009 |
5 / 5 (1) |
0
Recent studies have shown that the mitochondrial peptide Humanin (HN) protects against neuronal cell death such as happens in Alzheimer's disease. Now, in a study presented April 22 at Experimental Biology 2009 in New Orleans, ...
Huntington disease begins to take hold early on
Apr 16, 2009 |
5 / 5 (1) |
0
A global analysis of brain proteins over a 10-week period in a mouse model of Huntington Disease has revealed some new insights into this complex neurodegenerative disorder. For example, profound changes (comparable to those ...
Researchers find potential cause of heart risks for shift workers
Medicine & Health / Neuroscience
Mar 03, 2009 |
3.7 / 5 (3) |
0
(PhysOrg.com) -- Harvard researchers from Brigham and Women’s Hospital (BWH) and colleagues have identified the potential cause of the increased risk for cardiovascular and metabolic disease in shift workers. ...
Drugs may be 'magic bullet' for infants born with rare form of diabetes
Feb 03, 2009 |
5 / 5 (2) |
0
Infants born with a rare form of inherited diabetes might avoid irreversible damage to their pancreases if they are treated immediately with sulfonylurea drugs rather than insulin, according to a new report in the February ...
- Pages: 1
