Life Processes

Activity . Based on the two activities performed above, can we design an experiment to demonstrate that sunlight is essential for photosynthesis? So far, we have talked about how autotrophs meet their energy requirements. But they also need other raw materials for building their body.

Water used in photosynthesis is taken up from the soil by the roots in terrestrial plants. Other materials like nitrogen, phosphorus, iron and magnesium are taken up from the soil. Nitrogen is an essential element used in the synthesis of proteins and other compounds. This is Figure .

Experimental set-up (a) with potassium hydroxide (b) without potassium hydroxide (a) (b) taken up in the form of inorganic nitrates or nitrites. Or it is taken up as organic compounds which have been prepared by bacteria from atmospheric nitrogen.