Diabetes

New insight into the biology of insulin release

In a new study, Yale researchers challenge a long-held assumption about how insulin-producing cells in the pancreas sense and respond to glucose. Their findings could lead to changes in the way that scientists approach the ...

Psychology & Psychiatry

Genetic study reveals metabolic origins of anorexia

A global study, led by researchers at King's College London and University of North Carolina at Chapel Hill, suggests that anorexia nervosa is at least partly a metabolic disorder, and not purely psychiatric as previously ...

Diseases, Conditions, Syndromes

New look at atherosclerosis

Atherosclerosis is the slow and progressive narrowing of arteries due to plaque formation. The atherosclerotic plaque forms by local proliferation of leukocytes and vascular smooth muscle cells (VSMCs) in the vessel wall ...

Pediatrics

Growth failure in preterm infants tied to altered gut bacteria

Extremely premature infants who fail to grow as expected have delayed development of their microbiome, or communities of bacteria and other micro-organisms living in the gut, according to a new study published in Scientific ...

Oncology & Cancer

The declining impact of federal funding on cancer innovation

Cancer research is a field that has been especially dependent on public funding. The National Cancer Institute (NCI), an independent institute of the National Institutes of Health (NIH), was established in 1937 to provide ...

Medical research

A tale of two proteins: The best and worst of metabolic adaptation

The Developmental Origins of Health and Disease (DOHaD) hypothesis is supported by multiple human epidemiological studies and animal studies. It states that the nutritional environment in early life makes people susceptible ...

Diabetes

Tiny change has big effects, reverses prediabetes in mice

A small chemical change—shifting the position of two hydrogen atoms—makes the difference between mice that are healthy and mice with insulin resistance and fatty liver, major risk factors for diabetes and heart disease. ...

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Metabolism

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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