Sports medicine & Kinesiology

New strategy to facilitate muscle regeneration after injury

Muscle injuries are common in the active population, and they cause the majority of player retirements in the world of sports. Depending on the severity, recovery of muscle function is quite slow and may require surgery, ...

Medications

Mimicking exercise with a pill

Doctors have long prescribed exercise to improve and protect health. In the future, a pill may offer some of the same benefits as exercise. Now, researchers report on new compounds that appear capable of mimicking the physical ...

Health

Calcium intake and absorption: Are you getting enough?

Calcium is the most abundant mineral in the body. About 1% of the body's calcium is used for metabolic functions, such as vascular contraction and dilation, muscle function, blood clotting, heart rhythm, nerve transmission, ...

Health

Does intermittent fasting have benefits for our brain?

Intermittent fasting has become a popular dietary approach to help people lose or manage their weight. It has also been promoted as a way to reset metabolism, control chronic disease, slow aging and improve overall health.

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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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