How nitrogen-containing substances are made available to and are used by living organisms.
(25 marks)
Nitrogen is taken up by living organisms in the soil for the purpose of manufacturing proteins, nucleic acids and other nitrogen-containing compound. However, a vast minority of living organisms can use up the nitrogen gas directly, plants are only capable of absorbing the nitrogen-containing substances as nitrate ions, which are taken up from the soil via active transport. And so nitrogen enters the ecosystem through the absorption by plants and so theses plants are then eaten and digested by animals.
