Ecosystems — BIOLOGY STD 12 Science — Question

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

• Biological membranes.
• Nucleic acids.
• Energy transfer systems (like ATP and GTP).

2. The natural reservoir of phosphorus is rock.
3. 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,