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Nutrient cycle in environment

  BIO-GEO CHEMICAL CYCLE OR NUTRIENT CYCLE       Bio  -    Living organism       Geo  -    Rock, Soil, Air, Water Chemical   -  Material or Nutrients        Cycle   -   Path All the types of material required by ecosystem in addition of energy, are available continuously to system through recycling. Thus there is a constant exchange of materials between the living organism and their abiotic environment through the recyling of materials. This phenomenon is called Bio-geo chemical cycle. Note: Environment factors,e.g soil , moisture, ph, temperature etc, regulate the release of nutrients into the atmosphere. Biochemical cycle The following types of cycle are found in an ecosystem. (i) Gaseous Cycle - C, H, N. O cycles. Reservoir is in the atmosphere (air) or in Hydrosphere(water). Sedimentary cycle - P. S, Ca cycles reservoirs are in earth's crust (lithosphere). Note : ...
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DNA AS A GENETIC MATERIAL

   Hershey and chase performed their famous experiment to prove DNA not a protein it acts as genetic material


They selected bacteriophage T²  and E.coli for their experiment. They grew some bacteriophages on bacteria containg radio active phosphorus P³² and some on bacteria containg S³⁵ , radioactive sulphur.

The viruses grown in radioactive P³² medium incorporated it into their DNA. Similarly viruses grown on radioactive S³⁵ incorporate it in their protein coat.



Now these both types of viruses were allowed to infect bacteria separately. The infected bacterial cells were agitated in blender to remove the viral particle from them. The radioactivity was found only in the bacterial cells infected with P³² containg viruses.

It was found in the bacterial cells infected with S³⁵ protein cast viruses. 
This proves that  DNA acts as genetic material

DNA transfer experiment
Experiment for DNA as Genetic material


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