Women live longer than men. This simple statement holds a tantalizing riddle that Steven Austad, Ph.D., and Kathleen Fischer, Ph.D., of the University of Alabama at Birmingham explore in a perspective piece published in Cell ...
Other
Jun 14, 2016
24
996
(Phys.org) —What would you do with a camera that can take a picture of something and tell you how new it is? If you're Berkeley Lab scientists Katherine Louie, Ben Bowen, Jian-Hua Mao and Trent Northen, you use it to gain ...
Analytical Chemistry
Jun 13, 2013
0
0
Hummingbirds, native to North and South America, are among the smallest and most agile birds in the world. Often barely larger than a thumb, they are the only bird species that can fly not only forwards, but also backwards ...
Plants & Animals
Jan 12, 2023
1
408
To study certain aspects of cells, researchers need the ability to take the innards out, manipulate them, and put them back. Options for this kind of work are limited, but researchers reporting May 10 in Cell Metabolism describe ...
Bio & Medicine
May 10, 2016
0
760
A study of mice found that dietary sugar alters the gut microbiome, setting off a chain of events that leads to metabolic disease, pre-diabetes, and weight gain.
Cell & Microbiology
Aug 29, 2022
0
814
University of Adelaide researchers have shown that intelligence in animal species can be estimated by the size of the holes in the skull through which the arteries pass.
Evolution
Jul 15, 2015
3
187
(PhysOrg.com) -- Since the 1920s, scientists have known that cancer cells generate energy differently than normal cells, a phenomenon dubbed the 'Warburg effect' after its discoverer, German biochemist Otto Warburg. However, ...
Biochemistry
Apr 6, 2010
0
0
Even the simplest cell appears to be far more complex than researchers had imagined. In a series of three articles in the journal Science, researchers including Vera van Noort at the European Molecular Biology Laboratory ...
Cell & Microbiology
Dec 28, 2009
0
0
In a lecture he delivered in 1906, the German physician Paul Ehrlich coined the term Zuberkugel, or "magic bullet," as shorthand for a highly targeted medical treatment.
Bio & Medicine
Mar 12, 2010
0
0
(PhysOrg.com) -- First it was grapes, then cockroaches, and now snails have become the latest organism to generate electricity through an implanted biofuel cell. The process works similarly in all three situations: the electricity ...
Metabolism 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.
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