'Feeling' the living cell's life cycle using optical tweezers

Living cells are the basic building blocks of all organisms. We, as humans, are essentially a collection of trillions of living cells: and all these cells emerge from a single fertilized egg. This means that "mitosis" (or ...

Controlling carbs and fat: Learning from the fruit fly

Incretins are hormones secreted by intestinal cells that regulate pancreatic insulin and glucagon to control sugar metabolism in mammals. Although counterparts of insulin and glucagon have been identified in invertebrates, ...

Statins could be key to saving Tasmanian devils

Cholesterol-lowering drugs could help delay the spread of the deadly Tasmanian devil facial tumor disease (DFTD) and may help protect the endangered Australian marsupials from extinction, newly published research by QIMR ...

Single-cell test can reveal precisely how drugs kill cancer cells

Cancer cells are smart when it comes to anti-cancer drugs, evolving and becoming resistant to even the strongest chemotherapies over time. To combat this evasive behavior, researchers have developed a method named D2O-probed ...

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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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