Metabolism is the set of life-sustaining chemical reactions in organisms. The three main purposes of metabolism are: the conversion of food to energy to run cellular processes; the converted of foodfuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes.
About Metabolism in brief
Metabolism is the set of life-sustaining chemical reactions in organisms. The three main purposes of metabolism are: the conversion of food to energy to run cellular processes; the converted of foodfuel 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 and reproduce, maintain their structures, and respond to their environments. The metabolic system of a particular organism determines which substances it will find nutritious and which poisonous. The basal metabolic rate of an organism is the measure of the amount of energy consumed by all of these chemical reactions. A striking feature of metabolism is the similarity of the basic metabolic pathways among vastly different species. The metabolism of cancer cells is also different from the metabolism of normal cells and these differences can be used to find targets for therapeutic intervention in cancer. The basic structures that make up animals, plants and microbes are made from four basic classes of molecule: amino acids, carbohydrates, nucleic acid and lipids. As these molecules are vital for life, metabolic reactions either focus on making these molecules during the construction of cells and tissues, or by breaking them down and using them as a source of energy, by their digestion. These biochemicals can be joined together to make polymers such as DNA and proteins, essential macromolecules of life. For example, amino acids are made of amino acids arranged in a linear chain joined together by peptide bonds.
Proteins are also important in cell signaling, immune responses, cell adhesion, active transport across membranes, and the cell cycle. Amino acids also contribute to cellular energy metabolism by providing a carbon source for entry into the citric acid cycle. Carbohydrates are the most abundant and fill numerous roles, such as the storage and transport of energy and structural components. Each basic carbohydrate unit is composed of a phosphate group attached to a ribose or deoxyribose group. The two nucleotides are composed of polysaccharides and include glucose, galactides, fructose and galactactides. The most abundant molecules are the straight chains or rings that can exist as straight molecules, that can be linked together to form polymers. The sugars are the basic carbohydrate units are monoscharides, glucose, fructose, galactorides and most importantly glucose. The fats are a large group of compounds that contain fatty acids and glycerol; a Glycerol molecule attached to three fatty acid esters is called a triacylglyceride. Lipids are usually defined as hydrophobic or amphipathic biological molecules but will dissolve in organic solvents such as alcohol, benzene or chloroform. Steroids such as sterol are another major class of compounds, with many hydrophilic groups attached, that exist as aldehydes or hydhydes as in ketohydrates or ketol as in phosphol phosphol.