what is Nutritional requirements? uses of Nutritional requirements? types of Nutritional requirements?

All organisms require a source of energy some rely on chemical compounds for the energy and designated as chemotrops others can utilize radiant energy {light} are called phototrophs. Both chemo and phototrops exist among bacteria.
All organisms require a source of electron for their metabolism. Some organisms can use reduced inorganic compounds as electron donors and termed as a lithotrops {some maybe chemo and lithotrops}. Other organisms use organic compounds as electrons donors and are called organotrophs {some are chemo and photoorganotrophs}.
All organisms require carbon in some form for the use in synthesizing cell components. All organisms requires atleast small amounts of co2 .however some can use co2  as their major {or} events sole, source of carbon such organisms are termed as autotrophs. Others require organic compounds as their carbon source and termed as heterotrophs.
all organisms require nitrogen in some for cell components. Bacteria extremely versaitile in this respect. Unlike eukaryotes, some bacteria can be used atmospheric nitrogen.
All organisms require oxygen, sulphur and phosphorus for cell components.o2  is provided in various forms such as water, components atoms of various nutrients {or} molecular oxygen sulphon is needed for certain synthesis of certain amino acids.
All living organisms require metal ions such as k­­­+, ca2+, mg2+, and fe2+, for normal growth. Other metal ions are also needed but as usually only at very low concentrations such as zn2+, cu2+, mn2+, mo2+, ni2+, b+3, and ca+2 .these are often termed as trace elements and often occur as contaminants of other components of culture media in amount sufficient to support normal growth.
Most bacteria do not require na+ but certain marine bacteria cyanobacteria and photosynthetic bacteria do require it for those members of the archeabacteria bacteria known as red extreme halophiles. The requirement is astonishing they cannot grow with less than 12-15% nacl. They require these high levels of nacl for maintenance of the integrity of their cell walls and for the stability and activity of certain of their enzymes.
All living organisms contain vitamins and vitamins like compounds thus functions either as coenzymes for several enzymes {or} as building blocks for coenzymes. Some bacteria are capable of synthesizing their requirements of vitamins from the other compounds in their culture medium, but others cannot do so and will not grow unless the required vitamin are supplied performed to them in the medium.
all organisms require water and in the case of bacteria all nutrients must be in aqueous solution before their enter the cells water is highly polar compound that have unequalased in its ability to dissolve disperse cellular components and to provide is suitable mileu for the various metabolic reactions of the cell nutritional types of bacteria the major separation is into two types 1.phototrophs and 2.chemotrops 
chemotrops  among the chemotrophic bacteria are species that use inorganic compounds as the source of electron

Example :-

nitrosomonas use ammonia as their electron source
Nh­­4+  +3/2 o2 + h20 à  no-2  + 2h3o+  
Autotrops organisms that can use co2as their sole source of carbon for assimilation for autotrops.
Some autotrops are faculatative autotrops that have thecy can live as autotrops deriving their carbon from co2  {or} they can live as heterotrops deriving their carbon from organic compounds.

Heterotrophs:-

heterotrophic bacteria have more extensively than
The autrophic because hetrotrops species cause diseases of human beings, other animals and plants.
Hetrrotropic bacteria has one more major nutitional group specific
Nutrient required for growth, particular with respect to their organic carbon source nitrogen source and vitamins requirements.
Obligate parasites:-
The bacteria can be propagated only in association with a living host but not in artificial medium

Example:-

Mycobacterium leprae which can be cultivated by injecting mice {or} armadillos.
Types of media:-

Selective media:-

These media provides nutrients that enhance the growth and predominance of a particular type of bacterium and do not enhance other types of organisms that may be present.
A medium in which cellulose is the only carbon source with specifically select for {or} enrich the growth of cellulose utilizing organisms. Example:-neisseria gononhoeae facilitated by the use of media containing certain antibiotics there anti-biotic do not affect neisseria gononhoeae and do not inhibit the growth of contaminating bacteria

Differential media :-

Certain reagents or supplements which incorporate into culture media, may allow differentiation of various kinds of bacteria.

Example:- 

if a mixture of a bacteria is inoculated on to a blood containing agar medium.

Some of the bacteria may haemolyze {destroy}, the red blood cells other do not.
Thus one can distuinguish between hemolytic and non hemolytic bacteria on the same medium.

Enrichment media:-

One type of chemical method is to provide in culture medium a substrate that have a single carbon or nitrogen source this particular kind of selection is often referred to by a special name enrichment.

Example:-

 if we isolate soil bacteria capable of utilizing a very complex organic compound like alpha[α], conidendrin, constituent of wood, we prepared a liquid enrichment medium in which α conidendrin is the sole source of carbon under these conditions only organisms capable of utilizing this compound will be able to grow well.
If we select for nitrogen fixing bacteria nitrogen gas {n2} can be supplied as the sole nitrogen source, since only nitrogen fixing bacteria will be able to grow well.

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