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Ecosystems — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYEcosystems4 Marks
Question
  1. Name the specific cellular components, where phosphorus is in abundance in living organisms.
  2. Name the natural reservoir of phosphorus.
  3. Explain the phosphorus cycle.
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Answer

  1. The cellular components, where phosphorus is abundant include:

  • Biological membranes.
  • Nucleic acids.
  • Energy transfer systems (like ATP and GTP).
  1. The natural reservoir of phosphorus is rock.
  2. Phosphorus cycle:
  • The rocks contain phosphorus in the form of phosphates.
  • During weathering of rocks, some amount of phosphates dissolve in the soil solution and plants absorb them.
  • Herbivores and other carnivores obtain it directly or indirectly, plants.
  • The phosphate-solubilising bacteria release phosphorus back to the soil, when they decompose the dead and decaying organic matter.

Refer to Fig. 14.5 in the text,

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