NCERT Solutions for Class 11 Biology Chapter 12

1. Comment on the statement that ‘All elements that are present in the plant need not be essential to its survival. 

Ans: All elements are not directly involved in the composition of the plant's body that’s why they are essential to its survival. If the micronutrients concentration such as \[Zn,{\text{ }}Cl,{\text{ }}Fe,{\text{ }}Mn,{\text{ }}Cu,\]etc., rise above their critical values, they appear to be toxic for the plant.

2. In mineral nutrition studies using hydroponics, why is the purification of water and nutrient salts plays an important role? 

Ans: The important role played by the purification of water and nutrient salts are: 

• Hydroponics is a method of growing plants in the absence of soil in a nutrient solution. 

• Since the amount of solution is limited, there are chances of depletion of oxygen and mineral levels in the solution. 

• Hence, the purification of water and nutrient salts is important to maintain optimum growth in the plants.
  
  

3. Give some examples of macronutrients, micronutrients, beneficial nutrients, toxic elements and essential elements. 

Ans: Some examples are: 

• The nutrients such as carbon, hydrogen, oxygen, nitrogen, phosphorus, sulphur, potassium, calcium and magnesium are needed in large amounts by the body and are known as macronutrients. 

• The nutrients such as iron, manganese, copper, molybdenum, zinc, boron, chlorine and nickel are known as micronutrients.

• Any mineral ion is considered as a toxic element concentration if it reduces the dry weight of tissues by about 10% For example, the absorption of other elements can be inhibited by manganese concentration. 

• The plant nutrients that may not be essential, but are beneficial to plants are known as beneficial nutrients such as sodium, silicon, cobalt and selenium are beneficial to higher plants. 

• The macronutrients including carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur, potassium, calcium and magnesium are required directly for the growth and metabolism of the plants and their deficiency can cause certain symptoms in the plants.
  
  

4. Give five deficiency symptoms that occur in plants and describe them with the concerned mineral deficiency.

Ans:  The necrosis, stunted plant growth, premature fall of leaves and buds, and inhibition of cell division are some deficiency symptoms in plants. 

1. The loss of chlorophyll leading to yellowing in leaves is known as Chlorosis. The elements such as N, K, Mg, S, Fe, Mn, Zn and Mo can cause this deficiency. 

2. The deficiency of certain elements such as Ca, Mg, Cu, K can cause necrosis or death of tissue, particularly leaf tissue. 

3. Inhibition of cell division can be caused due to lack or low levels of N, K, S, and Mo. 

4. If the concentration of some elements like N, S, and Mo occur they can delay flowering in plants. 

5. The deficiencies of Cu and S cause stunted plant growth.
   
   

5. How would you find out experimentally that a plant shows a deficiency symptom due to one or more than one nutrient, the real deficient mineral element?

Ans: The steps are: 

• Every element shows certain characteristic deficiency symptoms in the plants. If an experimental set-up is prepared where several nutrient media is prepared where only one of the essential minerals is missing. 

• Also, one control medium is prepared where all the nutrient is present. 

• Now, we place a plant in each medium and record the deficiency symptoms according to the missing mineral element. 

• This tabular form will work as the standard information regarding the identification of deficiency symptoms. 

• Now we have to note down all the symptoms shown by any specific plant and match them with this standard data. 

• The similarities found will let us know which is the real mineral nutrient the plant is missing.
  
  

6. Why is it that in certain plants deficiency symptoms appear first in younger parts of the plant, while in other they do so in mature organs?

Ans: This is because of the facts that: 

• The older tissues show deficiency symptoms when the elements that are actively mobilised are exported to the young part. For example, the senescent leaves show the deficiency symptoms of nitrogen, potassium and magnesium.

• In the older leaves, these elements are available for mobilising to younger leave due to the breakdown of biomolecules containing these elements.

• When the elements are relatively immobile from the older parts, the young tissues show deficiency symptoms. For example, the structural component of the cell that contains elements like sulphur and calcium does not easily mobilise to the younger tissues.
  
  

7. How the absorption of minerals occurs in the plants? 

Ans: The mechanism of absorption of minerals can occur in two main phases. 

1. In the first phase, the apoplast is passive and uptake of ions into the ‘free space’ or ‘outer space’ of cells occurs. 

2. The ions are taken in slowly into the ‘inner space’ the symplast of the cells in the second phase. 

The ion channels, the transmembrane proteins that function as selective pores help in the passive movement. The expenditure of metabolic energy is required for the entry or exit of ions to and from the symplast. The inward movement of molecules into the cells is influx and the outward movement is efflux.

8. In what conditions atmospheric nitrogen can be fixed by Rhizobium and explain their role in Nitrogen-fixation? 

Ans:  

• The first essential condition for nitrogen fixation is the legume-bacteria relationship. 

• The enzymes necessary for nitrogen fixation are present in root nodules and thus enable rhizobium to fix nitrogen. 

• The conversion of nitrogen into ammonia is facilitated by the enzyme nitrogenase which is the first stable product of nitrogen fixation. 

• Ammonia is then converted into glutamic acid. The plants utilize glutamic acid and make amino acids; which are then utilised to make protein.
  
  

9. In the formation of a root nodule, what are the steps involved? 

Ans: The nodule formation involves many steps and a sequence of multiple interactions between Rhizobium and the roots of the host plant. The nodule formation steps are: 

• Firstly, the Rhizobia multiply and colonise the surroundings of roots and epidermal and root hair cells get attached to it. The bacteria invade when the root-hair curls. 

• The bacteria are carried into the cortex of the root when an infection thread is produced, where the nodule formation in the cortex of the root is initiated. 

• From the thread, the bacteria are released into the cells which lead to the differentiation of specialized cells for nitrogen fixation. 

• A direct vascular connection is formed with the host with the help of nodules which help in the exchange of nutrients.

10. Which of the following statements are true? If false, correct them. 

i. Boron deficiency leads to the stout axis. 

Ans. True

ii. The cell needs every mineral element that is present in it.

Ans. False 

Correct statement: Out of all the mineral elements, only 17 are considered essential elements.

iii. Nitrogen is highly immobile in plants in the form of nutrient elements.

Ans. False. 

Correct statement: Nitrogen is very much mobile in plants, as nitrogen is shifted from older parts to younger tissues.

iv. The micronutrients are required only in trace quantities so it is very easy to establish their essentiality.

Ans. True

NCERT Biology Class 11 Mineral Nutrition PDF

NCERT Solutions for Mineral Nutrition Class 11 Biology recommended by CBSE helps score well. Provided by Vedantu, Mineral Nutrition Class 11 NCERT Solution PDF format helps in easy referring to the various questions in the textbook. This in turn helps a student in active learning and understanding of the concepts which automatically results in securing higher marks. These solutions are helpful in the basic understanding of the subject and the answer format which would help any student in scoring better in academics.

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NCERT Solution Class 11th Biology Chapter 12 Mineral Nutrition

The fundamental needs of all living creatures are the same. They require macromolecules, for example, starches, proteins and fats and water and minerals for their development and advancement. This section focuses fundamentally on inorganic plant sustenance. Here, you will consider the techniques to recognize components that are basic to the development and advancement of plants and the rules for building up the vitality. You will likewise examine the function of the fundamental components, their significant lack of indications and the component of retention of these basic components. The section additionally acquaints you with the system of organic nitrogen fixation.

In 1860, Julius von Sachs, a known German botanist, illustrated unexpectedly that plants could be developed in a characterized supplement arrangement is complete nonattendance of soil. This procedure of developing plants in a supplement arrangement is known as tank-farming. Since then, various techniques have been utilized to attempt to decide the mineral supplements fundamental for plants. The quintessence of each one of these techniques includes the way of life of plants in a dirt-free, characterized mineral arrangement. These strategies require filtered water and mineral supplement like salts.

After a progression of tests wherein the underlying foundations of the plants were inundated in supplement arrangements and a component was included/eliminated or given in shifted fixation, a mineral arrangement appropriate for the plant development was acquired. By this strategy, basic components were distinguished and their inadequacy indications were found. Tank-farming has been effectively utilized as a strategy for the business creation of vegetables. It must be stressed that the supplement arrangements must be sufficiently circulated with air to get the ideal development.

Division of Marks for Mineral Nutrition Class 11 NCERT

The chapter falls under Unit 4 which has a weightage of 18 marks. One can expect either a basic 1 mark question or an elaborate 5 mark question.

Advantages of Class 11 Biology Mineral Nutrition NCERT Solution

Class 11 Biology Chapter 12 NCERT Solutions answers help students acquaint themselves with answering a particular question effectively. All the keys are solved by experts of the subject using proper instances. Students can refer to these solutions to associate their answers and rectify their mistakes. While formulating answers for exams, these solutions are the best study resource that can be blindly trusted. NCERT Solution for Class 11 Biology Chapter 12 Mineral Nutrition covers all the queries mentioned in Ch 12 Bio Class 11 NCERT Solution. Solving the sample questions given at the end of each chapter is vital to comprehend the concepts and learn them.