Cellular Pool



 THE CELLULAR POOL:

Various  type of chemicals  or molecules  present in  the   living organisms are known as  biomolecules and collection of different  types of biomolecules, compounds  or ions present in a cell are called the cellular Pool.

The aggregation of the various kinds of biomolecules in a cell is referred  to as the cellular poolCellular pool has two phases:

(a) Aqueous  phase : It contains  chemical  dispersed in water forming  either true solution or colloidal solution. 


(b) Non_ aqueous phase: It contains chemical  deposited  in  various structures like chromatin, cell membrane and cell wall.


 Cellular pool consists  of two types of biomolecules: inorganic  and organic. 

(i) Inorganic: The inorganic  compounds  usually  lack the elements  carbon. They have relatively small molecules with simple structure  and low molecules weights. They include water, mineral  salts and ions, and gases.

(ii) Organic: The organic compounds contain  the element carbon. The carbon atoms are bonded to form a string ( chain) or ring which serves as a " skeleton " for organic molecule. The most of their  carbon atoms are also bonded to one or more hydrogen  atoms. The organic compounds are chiefly formed by living organisms, hence their name. They have large molecules with complex structure and high molecular weights. They include carbohydrates, lipids , proteins,  nucleotides , nucleic acids, and vitamins.




 Chemicals of cellular Pool are obtained from outside through  selective from outside through  selective  intake by cell  through  membranous covering of cell organelles  and plasma membranes. The  membranes possess selective permeability and retentivit. Chemicals of cellular Pool function  as raw material  for various  reactions  of cell organelles and cell.Depending upon their molecular  weight and solubility, biomolecules are of two types: 

(a) Micromolecules: They are small sized chemical  having  low molecular weight,  and higher solubility. They include water, gases, minerals, sugars, amino acids and nucleotides. 

(b) Macromolecules : They are large sized complex  chemicals  having a high molecular weight,  low solubility  and complex conformation.They include  four  classes of organic compounds viz., carbohydrates lipids, proteins and nucleic  acids. Except lipids other  macromolecules are formed by the polymerization  of monomer subunits. Three _ dimensional  shapes of macromolecules enable them to function as structural components, nutrient stores, energy source, enzymes, molecular messenger and storehouse  of genetic information etc.
 


Composition:

The cellular Pool comprises   over 5000 chemicals. These include both  inorganic and organic molecules. The inorganic molecules generally occur in both aqueous and nonaqueous phases.


Maintenance  of Pool's Composition:

The cell maintains  the composition of its pool by taken up and eliminating specific molecules through its semipermeable plasma membrane. This steady state within the cell is essential  for its survival.  The cellular Pool provides  all the necessary  materials  for the structure  and functions  of the cells.

The composition of the  cellular Pool in animal cell is  quite different  from that of the extracellular fluid. The difference  is maintained by the cell membrane through its selective  permeability. 

How to Analyse Chemical  Composition?

One has to perform  a chemical  analysis.  We can take any living  tissue ( a vegetable  or a piece of liver, etc.) and  grind it in trichloroacetic acid ( CI3CCOOH) using a mortar and a pestle. We obtain thick slurry. If we were to strain this through a cheesecloth or cotton  we would obtain two fractions. One is called the filtrate or more technically, the acid__ soluble pool, and the second, the retentate or the acid insoluble fraction. Scientists have found thousands  of organic  components in the acid__ soluble pool.

     Living organisms have also got inorganic elements and compounds in them. How do we know this? A slightly  different  but destructive  experiment has to be done. One weighs a small  amount  of a living  tissue ( say a leaf or liver and this is called wet weight) and dries it . All the water evaporates. The remaining material  gives dry weight.Now if the tissue is fully burnt, all the carbon compounds  are oxidized to gaseous from ( CO2, water vapour) and are removed. What is remaining  is called ' ash'. This ash contains  inorganic elements (like calcium, magnesium etc.) Inorganic  compounds  like sulphate, phosphate,  etc., are also seen in the acid_ soluble fraction. Therefore,  elemental analysis  gives elemental composition of living  tissues in the form of  hydrogen  , oxygen, chlorine, carbon etc. while analysis for compounds gives and an idea  of the kind of organic and inorganic  constituents present in living  tissues. 





































































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