Question

With the help of examples describe the classification of essential elements based on the function they perform.

Answer 1

Essential elements can also be grouped into four broad categories on the basis of their diverse functions.

These categories are:

1. Essential elements as components of biomolecules and hence structural elements of cells (e.g., carbon, hydrogen, oxygen and nitrogen).
2. Essential elements that are components of energy-related chemical compounds in plants (e.g., magnesium in chlorophyll and phosphorous in ATP).
3. Essential elements that activate or inhibit enzymes, for example, \[\ce{Mg^{+}2}\] is an activator for both ribulose bisphosphate carboxylase/oxygenase and phosphoenol pyruvate carboxylase, both of which are critical enzymes in photosynthetic carbon fixation; Zn⁺ is an activator of alcohol dehydrogenase and Mo of nitrogenase during nitrogen metabolism.
4. Some essential elements can alter the osmotic potential of a cell. Potassium plays an important role in the opening and closing of stomata. Minerals also play the role of solutes in determining the water potential of a cell.