Question

which of the following is chemical requirements for Growth

Answer 1

Ans.

All microorganism has the ability to grow and form their own population, provided they get an adequate amount of nutrients required for their growth.There are two types of requirements that a microorganism has for their optimal growth;physical requirements and chemical requirements.Let now understand the various chemical requirements for growth.

Following are the chemical requirements for the growth of microorganisms:

1. Carbon -About 50% of the cells dry weight in any microorganism is due to the presence of carbon.Carbon forms the structural backbone of the the organic compounds,whether they are proteins,fats,lipids or carbohydrates.Microorganisms obtain carbon either from the organic materials available in the environment or derive from carbon dioxide.Chemoautotrophic and photoautotrophic organisms produces their nutrients from carbon dioxide,the only difference being the way they do so.While chemoautotrophs obtain energy through chemical reactions,photoautotrophs use photosynthesis to obtain their energy.
2. Nitrogen,Phosphorus and Sulfur - Nitrogen is another important chemical that makes up near about 14% of the cell's dry weight and is utilized for the synthesis of amino acids,DNA and RNA.Bacteria obtain nitrogen through the process of nitrogen-fixing and such bacteria are called as nitrogen-fixing bacteria,such as Rhizobium and Azotobacter.Phosphorus is again the chemical vital for the synthesis of DNA,RNA ,phospholipids and ATP and is derived mainly from inorganic phosphate salts and buffers.Sulfur is important for the synthesis of vitamins like biotin and thiamin,and proteins and their main sources are sulfates,hydrogen sulfide and proteins.
3. Oxygen -Organisms that undergoes respiration aerobically uses molecular oxygen and produces energy that is comparatively more as compared to anaerobic organisms.Microorganisms that grows in the absence of oxygen produces other odoriferous gases like hydrogen sulfide and methane for their metabolism purpose.Certain organisms are called facultative because they can grow either in the presence of oxygen or in the absence of oxygen,using fermentation.
4. Trace elements such as iron,copper,zinc and enzyme cofactors -Trace elements are mostly required for the synthesis of enzymes that are involved in various vital biochemical reactions.Vitamins acts as organic growth factors and are required by certain bacteria.Other trace elements includes amino acids,purines and pyrimidines.