Metabolism and Energy Transformation in Body Cells - Renata Armenakovna Petrosova 2004

Metabolism and Energy Transformation as a Fundamental Property of Living Systems
The Concept of Metabolism and Energy Transformation

One of the Characteristic Features of Living matter is METABOLISM and Energy conversion. Metabolism (from the Greek metabolē meaning change or turn) is the sum total of all Synthesis and degradation reactions occurring in living systems, accompanied by the release or absorption of energy. Organisms require nutrients and energy from their external environment to survive. Through Nutrition and Respiration, specific substances enter the Organism where, As a result of vital activity, they are transformed, partly stored, and partly released back into the environment. Energy and nutrients are essential for carrying out all life processes of an organism, such as growth, development, movement, reproduction, etc. The foundation of all these processes is metabolism and energy conversion.

A living system, which any organism is, maintains a complex relationship with its environment. It obtains food, Water, oxygen, light, and heat from the environment. From these incoming substances and energy, organisms build their bodies, forming the mass of living matter on the planet. Through their vital activity, organisms themselves affect and modify the environment. The foundation of the interaction between living systems and their environment is metabolism and energy conversion.

Metabolism is also characteristic of inanimate nature. For example, metabolism occurs during the weathering and erosion of rocks. Under the action of water, carbon dioxide, and other agents, large complex rocks break down and transform into sand and clay. Chemical substances undergo oxidation, such as iron rusting. When they burn, gaseous products and water are formed and released into the atmosphere.

The fundamental difference between metabolism in inanimate and living nature is that metabolic processes in inanimate nature lead to the destruction and breakdown of matter and rock. In contrast, living organisms, owing to metabolism, create new substances, sustain their lives, and reproduce their own kind.

Metabolism and energy conversion consist of two interrelated and opposing processes: assimilation and dissimilation. Assimilation, anabolism, or plastic metabolism is the set of synthesis reactions involving high-molecular-weight Organic compounds, accompanied by the absorption of energy derived from The breakdown of ATP molecules. Dissimilation, Catabolism, or Energy Metabolism is the set of Breakdown and Oxidation reactions of organic substances, accompanied by the release of energy and its storage in newly synthesized ATP molecules. These processes are characteristic of living systems at almost all Levels of Organization, ranging from The Cell to the biosphere (Fig. 1).

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Fig. 1. General scheme of metabolism and energy conversion

Assimilation and dissimilation are opposing yet interconnected processes that constitute The Unity of metabolism. In living nature, this is a closed-loop process because the chemical elements used to synthesize organic compounds are passed from one organism to another or released into the environment and subsequently reabsorbed by organisms. Thus, a continuous cycling of matter and chemical elements takes place.