Blocking cellular communication stops SARS-CoV-2

In the transmission of signals within the cell which, for example, stimulate cell growth or trigger metabolic processes, phosphate groups play an important biochemical role. The phosphate groups are often attached to proteins ...

Evolution in real-time: How bacteria adapt to their hosts

Bacteria that invade animal cells in order to multiply are widespread in nature. Some of these are pathogens of humans and animals. In the environment, they are often found inside unicellular organisms. A research team led ...

Scientists discover ancient enzymes evolve new tricks

Plants, herbivores, and pathogens are locked in a war for survival that is hundreds of millions of years old. Rooted in place and with no way to run, plants evolved complex, chemical-producing machinery in their cells to ...

Biologists shed light on how cells move resources

Florida State University researchers have new insight into the tiny packages that cells use to move molecules, a structure that is key to cellular metabolism, drug delivery and more.

Cellular stress causes cancer cell chemoresistance

There is a broad range of mechanisms associated with chemoresistance, many of which to date are only poorly understood. The so-called cellular stress response—a set of genetic programs that enable the cells to survive under ...

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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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