If you’re asked what’s going on in your body right now, your answer might be that you feel tired, or you’re hungry and so on. But let’s go even deeper, moving past the layer of your consciousness and looking at what’s going in your cells.

In your body every cell is working hard, energy is being transformed inside your cells, changing forms as molecules undergo the connected chemical reactions that keep you alive and functional.


What is Metabolism?


Cells are constantly carrying out thousands of chemical reactions needed to keep the cell, and our body as a whole, alive and healthy. These chemical reactions are often linked together in chains, or pathways. All of the chemical reactions that take place inside of a cell are collectively called the cell's metabolism[1].

The three main purposes of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks for proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow on reproduce, maintain their structures, and respond to their environments[2].


Types of Metabolism


Metabolic reactions may be categorized as catabolism or anabolism. Catabolism is the breaking down of the substances for energy or structure to get back to the building blocks. Anabolism is the rebuilding of the substances in ways that we find useful. Usually, catabolism releases energy, and anabolism consumes energy. A sketch of the catabolism of three macromolecules is as follows:


Fig.1 A sketch of the catabolism of proteins, polysaccharides and fats


In the metabolic pathways, enzymes are crucial to metabolism because they act as catalysts to allow organisms to drive desirable reactions that require energy and will not occur by themselves, by coupling them to spontaneous reactions that release energy.


Metabolism in Microorganism


Metabolism occurs not only in mammals, but also in microorganisms. The figure below shows the catabolism in E.coli, it is also complex. on  we can't see a cell, it is constantly engaged in metabolic activity to maintain its vitality. Scientists obtain the target products by altering the metabolic pathways of microbes.


Fig.2 Catabolism in E.coli




[1] P Mayes, D Bender. Overview of metabolism[J]. Shimonoseki City University Review, 2003, 54:51-60.

[2] MAJ, Georgia, RicardoC. Angiogenesis, Metabolism & Cancer 2012: Cell Symposia: Angiogenesis, Metabolic Regulation, and Cancer Biology in Association with VIB. 2013.

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