6. Biomolecules- part 06 - Concept of Metabolism

 

6. Biomolecules- part 06 - Concept of Metabolism



Concept of Metabolism: 

  • Metabolism is the sum of the chemical reactions that take place within each cell of a living organism and provide energy for vital processes and for synthesizing new organic material.
  • It involves continuous process of breakdown and synthesis of biomolecules through chemical reactions. 
  • Each of the metabolic reaction results in a transformation of biomolecules.
  • Most of these metabolic reactions do not occur in isolation but are always linked with some other reactions. 
  • In living systems, cells are ‘work centres’ where metabolism involves two following types of pathways.
  1. Catabolic pathway
  2. Anabolic pathway 

Catabolic pathway :
  • It leads to formation of simpler structure from a complex biomolecules
  • e.g. when we eat wheat, bread or chapati.
  • our gastrointestinal tract digests (hydrolyses) the starch to glucose units with help of enzymes and releases energy in form of ATP (Adenosine triphosphate).

Anabolic pathway :

  • It is called biosynthetic pathway that involves formation of a more complex biomolecules from a simpler structure.
  • e.g., synthesis of glycogen from glucose and protein from amino acids. 
  • These pathways consume energy.

Metabolic pool : 

  • It is the reservoir of biomolecules in the cell on which enzymes can act to produce useful products as per the need of the cell. 
  • The concept of metabolic pool is significant in cell biology because it allows one type of molecule to change into another type.
  • e.g. carbohydrates can be converted to fats and vice-versa.
  • Catabolic chemical reaction of glycolysis and Krebs cycle only provide ATP but also makes available metabolic pool of biomolecules that can be utilized for synthesis of many important cellular components. 
  • The metabolites can be added or withdrawn from this pool according to the need of the cell. 
  • The balance between catabolism and anabolism maintain homeostasis in the cell as well as in the whole body.

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