Question

In which of the following all three are macronutrients?
A. Boron, zinc, manganese
B. Iron, copper, molybdenum
C. Molybdenum, magnesium, manganese
D. Nitrogen, potassium, phosphorus

Answer 1

Hint: Macronutrients are the essential elements required by organisms in large amounts. Macronutrients are essential for the overall growth and a good state of the organisms. The macronutrients are essential for plant development since it plays a fundamental role in energy metabolism.

Complete answer:
Nutrients are chemical substances absorbed by plants for their growth and development. It is divided into two categories:
Macronutrients: The elements which are required in large amounts by plants are known as macronutrients. It includes carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.
Carbon, Hydrogen and Oxygen: constitute an essential part of carbohydrates and are also present in proteins and fats.
Nitrogen: it is part of proteins and nucleic acids and also used in the synthesis of some vitamins.
Phosphorus: present in nucleic acids, coenzymes, phospholipids and organic molecules of ATP. It plays an important role in metabolism by converting food energy to be converted into chemical energy through oxidative phosphorylation.
Potassium: play a key role in regulating the stomatal opening and closing.
Calcium: it is important in the synthesis of pectin in the middle lamella of the cell wall.
Sulfur: is an important constituent of some proteins and vitamins.
Magnesium: It is required in leaves.
Micronutrients: The elements which are required in small amounts by plants. It is also known as trace minerals/elements. It includes manganese, boron, molybdenum, copper, zinc and chlorine.
Boron: it is involved in carbohydrate transport in plants.
Chlorine: is important for osmosis and ionic balance and also plays a role in photosynthesis.
Copper is a constituent of some enzymes.
Iron: is important for chlorophyll synthesis and it is also the constituent of ferredoxin and cytochrome.
Manganese: important for activation of enzymes involved in chlorophyll formation. Molybdenum: it reduces nitrates into usable forms important for plant health.
Zinc: it is involved in chlorophyll formation and activation of many enzymes.

So, the correct answer is (D) Nitrogen, Potassium, Phosphorus.

Note:
Carbon, hydrogen and oxygen are non-mineral elements. Nitrogen is derived from both mineral and non-mineral sources. Role of nutrients are as follows:
> Balancing function
> Maintenance of osmotic pressure
> Influencing the pH of the cell sap
> Construction of the plant body
> Catalysis of the biochemical reaction