Mineral Nutrition: Class 11 Biology NCERT Chapter 12

Key Features of NCERT Solutions for Class 11 Biology Chapter 12 – Mineral Nutrition

In the previous chapter 11: Transport In Plants, you learnt about how transportation in plants happen. In this chapter: Mineral Nutrition, it centers around mineral sustenance in plants. Understudies definitely realize that one needs certain minerals and supplements so as to grow appropriately.

Correspondingly, they are likewise basic for the advancement of an individual. Hence, this part will give you how you need the equivalent for plants also. It will acquaint understudies with how plants additionally require supplements so they may create and perform works proficiently. Along these lines, mineral sustenance class 11 notes will empower understudies to consider it in detail. It moves the viewpoint towards plants which gives us a superior comprehension of their working. 

You can say that practically all living life forms have a similar essential needs. At the end of the day, every one of them need macromolecules like carbs, fats, minerals, proteins and more for their growth. Also, this section causes to notice one of those living life forms, plants. Here, you will be instructed about the strategies for distinguishing components that are fundamental for plant growth and advancement. Moreover, you will likewise concentrate how the job of these components is fundamental and what will occur in their inadequacy. Above all, you will likewise examine the significance and component of natural nitrogen obsession in mineral nourishment class 11 notes.

Sub-topics covered under Mineral Nutrition 

Fundamental Mineral Elements–This subject assists understudies with finding out about other basic components other than carbs, proteins, and fats for endurance known as components. 

Digestion of Nitrogen–Students will contemplate another predominant component in living creatures known as Nitrogen here.

 Quick revision notes

Essential Mineral Elements

Up until this point, 105 components have been found, of which in excess of 60 exist in plants. Yet, are for the most part these important for plants? How would we know which minerals are fundamental for plants and which are most certainly not? There are sure rules to decide this. We should realize what they are.

Criteria For Essentiality

  • The component must be basic for the growth and improvement of the plant. The plant can not finish its life cycle or produce seeds without the component. 
  • The necessity for the component must be explicit and not replaceable by another component. This implies the lack of one component can’t be remunerated by providing some other component. 
  • The component must have an immediate job in the digestion of the plant.

As indicated by the previously mentioned standards, just a couple of mineral components were seen as totally fundamental for plant growth and advancement. In light of the amount in which these minerals are required, they are additionally named follows.


These are available in plant tissues in enormous (full scale) sums (for example more than 10mmole/kg of dry issue). Macronutrients incorporate carbon, hydrogen, nitrogen, oxygen, sulfur, phosphorus, calcium, potassium and magnesium. Carbon, hydrogen and oxygen are retained from CO2 and H2O while the others are assimilated from the dirt.


These are required in little (smaller scale) sums (for example under 10mmole/kg of dry issue). In this way, they are additionally called minor components. Micronutrients incorporate iron, copper, manganese, molybdenum, chlorine, nickel, zinc and boron. 

All the 17 components referenced above are basic components. Notwithstanding these, components, for example, sodium, silicon, selenium and cobalt are likewise significant for higher plants.

Nitrogen Metabolism

The dirt has restricted measures of nitrogen. Plants and microorganisms vie for this nitrogen. Consequently, it is a restricting supplement for both farming and regular environments. How about we see how this accessible nitrogen is cycled in the biological system an idea known as nitrogen digestion

Peruse more Topics under Mineral Nutrition

  • Essential Mineral Elements

Nitrogen Cycle

The principle part of nitrogen digestion is the Nitrogen Cycle. A particle of nitrogen is made of two nitrogen iotas held together by a solid triple covalent bond (N ≡ N). There are three principle pools of nitrogen – climate, soil and biomass. Nitrogen cycles between these pools in the accompanying way:

Atmospheric Pool

The way toward changing over environmental nitrogen (N2) to alkali (NH3) is ‘Nitrogen obsession’. Environmental nitrogen is fixed in three different ways – natural, modern and electrical. 

  • Natural nitrogen obsession’ includes living beings that decrease nitrogen to smelling salts.
  • ‘Modern nitrogen obsession’ includes mechanical ignitions, vehicle depletes, backwoods flames and force producing stations as wellsprings of nitrogen. 
  • ‘Electrical nitrogen obsession’ is when powers of nature, for example, lightning and bright radiation give vitality to change over nitrogen to nitrogen oxides.

Soil Pool

The above procedures fix barometrical nitrogen into the dirt. This nitrogen is then taken up by plants and creatures, subsequently.

Biomass Pool

At the point when plants and creatures pass on, the natural nitrogen inside them breaks down to smelling salts. This procedure is ‘Ammonification’ and it returns nitrogen back to the dirt. A portion of this smelling salts vanishes and reenters the climate while a significant piece of it is changed over by soil microscopic organisms into nitrate as follows:

(i) First, ammonia is oxidised to nitrite by the bacteria Nitrosomonas and/or Nitrococcus.

2NH3 + 3O2 → 2NO2– + 2H+ + 2H2O

(ii) Then, nitrite is further oxidised to nitrate by Nitrobacter.

2NO2– + O2 → 2NO3–

These responses are called ‘Nitrification’ and the nitrifying microscopic organisms are ‘Chemoautotrophs’. Plants ingest the nitrate in this manner shaped and transport it to the leaves where it is diminished to smelling salts. This smelling salts shapes the amine gathering of amino acids. Nitrates in the dirt are additionally decreased to nitrogen during ‘Denitrification’ by Pseudomonas and Thiobacillus. Along these lines, nitrogen continues cycling in the biological system.

Mineral Nurition

                                                                     (Mineral Nutrition: Class 11 Biology)

Biological Nitrogen Fixation

Just a couple of prokaryotes can utilize the climatic nitrogen as N2 and decrease it to smelling salts. This decrease of nitrogen to smelling salts by living life forms is ‘organic nitrogen obsession’. The compound it requirements for this response – nitrogenase is available only in prokaryotes and these microorganisms are called N2 – fixers. These N2 – fixers can be advantageous or free-living. A few instances of free-living N2 – fixers are Azotobacter, Bacillus, Anabaena, Nostoc and so forth. 

Symbiotic Biological Nitrogen Fixation

Nodule Formation

The most well known model in this classification is the harmonious connection among Rhizobium and the foundations of vegetables, for example, sweet pea, garden pea, lentils. The affiliation is noticeable as knobs (little outgrowths) on the roots. Another model is the organism Frankia that additionally delivers nitrogen-fixing knobs on the underlying foundations of non-leguminous plants. 

Did you realize that in the event that you slice through a knob, its focal part is red or pink? What gives it this shading? It is the nearness of leguminous hemoglobin or leg-hemoglobin. We should get familiar with somewhat more about these knobs.

Another type of nitrogen digestion is knob development. Knob development includes a few communications between the underlying foundations of the host plant and Rhizobium. They are:

  • The Rhizobia duplicate, colonize and append themselves to the epidermal and root-hair cells of vegetables. 
  • The root-hair twists permitting the microorganisms to attack, make a disease string and arrive at the cortex of the root. Here the microscopic organisms start knob development. 
  • The contamination string at that point delivers the microorganisms into the phones. This prompts the separation of exceptional nitrogen-fixing cells. Along these lines, the knob sets up an immediate association for trade of supplements with the host. 
  • The knob contains the catalyst nitrogenase which changes over environmental nitrogen to the main stable result of nitrogen obsession – smelling salts. The response is:

N2 + 8e– + 8H+ + 16ATP —→ 2NH3 + H2 + 16ADP + 16Pi

The vitality required for the above response (8ATP for each NH3 delivered) originates from the breath of host cells. Additionally, the compound nitrogenase is exceptionally delicate to sub-atomic oxygen and subsequently needs anaerobic conditions. The oxygen-forager called leg-hemoglobin shields nitrogenase from oxygen in the knobs. 

Strangely, this microorganism lives as high-impact, free-living life form where nitrogenase isn’t practical. In any case, during nitrogen-obsession, they become anaerobic, in this way shielding the chemical from oxygen.

Fate of Ammonia

What befalls the smelling salts produced after nitrogen-obsession? It is protonated to shape ammonium particle (NH4+) at physiological pH. In spite of the fact that plants can aggregate nitrate and NH4+ particles, NH4+ particles are poisonous to them. In this way, it is thusly, used to blend amino acids in plants as follows: 

(I) Reductive amination: Here, alkali responds with α-ketoglutaric corrosive to shape glutamic corrosive within the sight of the chemical – glutamate dehydrogenase. 

α-ketoglutaric corrosive + NH4+ + NADPH → glutamate + H2O + NADP 

(ii) Transamination: Here, the amino gathering of one amino corrosive is moved to the keto gathering of a keto corrosive within the sight of the catalyst – transaminase. Asparagine and glutamine – the two most significant amides in plants emerge from two amino acids – aspartic corrosive and glutamic corrosive, individually. Another NH2–radicle replaces the hydroxyl gathering of the corrosive to give an amide. The xylem at that point ships these amides that contain more nitrogen to various pieces of the plant.


Question: What is the procedure of the decrease of nitrates in the dirt to nitrogen?

  1. Nitrification
  2. Nitrogen fixation
  3. Ammonification
  4. Denitrification

Solution: The appropriate response is “D”. Denitrification brings about the change of nitrates in the dirt to nitrogen.

(Mineral Nutrition: Class 11 Biology)

REEII ©  All rights reserved.