Question

What are the categories of essential elements in mineral nutrition?

Answer 1

Categories of Essential Elements:
* As components of biomolecules, e.g. carbon, hydrogen, oxygen and nitrogen. These are structural elements of cells.
* As components of energy-related chemical compounds, e.g. magnesium in chlorophyll and phosphorous in ATP.
* Elements which activate or inhibit enzymes, e.g. $M{g}^{2+}$ activates RUBISCO and phosphenol pyruvate carboxylase. Similarly, $Z{n}^{2+}$ activates alcohol dehydrogenase.
* Elements which alter osmotic potential of a cell, e.g. potassium plays an important role in opening and closing of stomata.