NCERT Exemplar Class 11 Biology Solutions Chapter 12 Mineral Nutrition
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Download PDFNCERT Exemplar Class 11 Biology solutions chapter 12 studies chemical elements and compounds pivotal for plant growth and metabolism. You will be amazed to know that plants absorb 105 elements out of which 17 elements are important for growth and survival. Along with these, plants also need beneficial elements such as sodium, silicon, cobalt etc. NCERT Exemplar Class 11 Biology solutions chapter 12 also explains the absorption mechanism of elements in the plant. Plants also require Macro and Micronutrients for their proper well-being. Macronutrients such as Carbon, Oxygen, Nitrogen, Sulphur, Potassium, Calcium and Magnesium are required in large amounts for plant growth. Micronutrients namely Manganese, Copper, Zinc, Boron, Nickel, are present in fewer amounts.
NCERT Exemplar Solutions for Class 11th Biology Chapter 12 Mineral Nutrition:
Multiple Choice Questions:
Question:1
Which one of the following roles is not characteristic of an essential element?
(a) Being a component of biomolecules
(b) Changing the chemistry of soil
(c) Being a structural component of energy related chemical compounds
(d) Activation or inhibition of enzymes
Answer:
The answer is the option (b) changing the chemistry of soilExplanation: Essential elements have no role in changing the chemistry of soil because soil is a non-living thing.
Question:2
Which one of the following statements can best explain the term critical concentration of an essential element?
(a) Essential element concentration below which plant growth is retarded.
(b) Essential element concentration below which plant growth becomes enhanced.
(c) Essential element concentration below which plant remains in the vegetative phase.
(d) None of the above
Answer:
The answer is the option (a) essential element concentration below which plant growth becomes retarded.Explanation: Critical concentration is the limited concentration of essential elements in a plant that is required for its proper growth and development. If the concentration falls below this level, growth will be stunted or retarded.
Question:2
Which one of the following statements can best explain the term critical concentration of an essential element?
(a) Essential element concentration below which plant growth is retarded.
(b) Essential element concentration below which plant growth becomes enhanced.
(c) Essential element concentration below which plant remains in the vegetative phase.
(d) None of the above
Answer:
The answer is the option (a) essential element concentration below which plant growth becomes retarded.Explanation: Critical concentration is the limited concentration of essential elements in a plant that is required for its proper growth and development. If the concentration falls below this level, growth will be stunted or retarded.
Question:3
Deficiency symptoms of an element tend to appear first in young leaves. It indicates that the element is relatively immobile. Which one of the following elemental deficiency would show such symptoms?
(a) Sulphur
(b) Magnesium
(c) Nitrogen
(d) Potassium
Answer:
The answer is the option (a) SulphurExplanation: Elements other than Sulphur are highly mobile and they move from old leaves to the young.
Question:4
Which one of the following symptoms is not due to manganese toxicity in plants?
(a) Calcium translocation in shoot apex is inhibited
(b) Deficiency in both Iron and Nitrogen is induced
(c) Appearance of brown spot surrounded by chlorotic veins
(d) None of the above
Answer:
The answer is option (d) None of the aboveExplanation: Toxicity of manganese occurs when plants absorb manganese in large amounts. This high intake causes deficiency in Iron and Nitrogen, Ca translocation in the shoot apex, brown spots surrounded by chlorotic veins.
Question:5
Reaction carried out by N2 fixing microbes include
Which of the following statements about these equations is not true?
(a) step (i) is carried out by Nitrosomonas or Nitrococcus
(b) step (ii) is carried out by Nitrobacter
(c) both steps (i) and (ii) can be called nitrification
(d) bacteria carrying out these steps are usually photoautotrophs
Answer:
The answer is the option (d) bacteria carrying out these steps are usually photoautotrophsExplanation: Bacteria carrying out nitrogen fixation are chemoautotrophs and not photoautotrophs.
Question:6
With regard to the Biological Nitrogen Fixation by Rhizobium in association with soybean, which one of the following statement/ statements does not hold true.
(a) Nitrogenase may require oxygen for its functioning.
(b) Nitrogenase is Mo- Fe protein
(c) Leg-hemoglobin is a pink coloured pigment.
(d) Nitrogenase helps to convert N2 gas into two molecules of ammonia.
Answer:
The answer is the option (a) Nitrogenase may require oxygen for its functioningExplanation: Nitrogenase is highly sensitive to oxygen. If exposed to oxygen, it makes the enzyme inactive. Therefore, nitrogenase does not require oxygen for its functioning.
Question:7
| Column I | Column II |
| A. Boron | (i) Splitting of H2O to liberate O2 during photosynthesis |
| B. Manganese | (ii) Needed for synthesis of auxins |
| C. Molybdenum | (iii) Component of nitrogenase |
| D. Zinc | (iv) Pollen germination |
| E. Iron | (v) Component of ferredoxin |
Options
(a) A-(i), B-(ii), C-(iii), D.(iv), E-(v)
(b) A-(iv), B-(i), C-(iii), D-(ii), E-(v)
(c) A-(iii), B-(ii), C-(iv), D-(v), E-(i)
(d) A-(ii), B-(iii), C-(v), D-(i), E-(iv)
Answer:
(b) A-(iv), B-(i), C-(iii), D-(ii), E-(v)
| Pollen germination |
| Splitting of H2O to liberate O2 during photosynthesis |
| Component of nitrogenase |
| Needed for synthesis of auxins |
| Component of ferredoxin |
Question:8
Plants can be grown in (Tick the incorrect option)
(a) Soil with essential nutrients.
(b) Water with essential nutrients.
(c) Either water or soil with essential nutrients.
(d) Water or soil without essential nutrients.
Answer:
The answer is the option (d) water or soil without essential nutrients.Explanation: Plants cannot grow in water or soil without essential nutrients because lack of nutrients will
lead to no growth.
Very Short Answer Type Questions:
Question:1
Name a plant, which accumulate silicon.
Answer:
Oryza sativa (Rice).Question:2
Answer:
Mycorrhiza is a symbiotic or mutualistic association between fungus and roots of vascular plants. In this association, the roots provide shelter to the fungus, and fungus helps the roots in intake of minerals, water, and other nutrients.Question:3
Nitrogen fixation is shown by prokaryotes and not eukaryotes. Comment?
Answer:
Nitrogenase is the enzyme which is required for nitrogen fixation. This enzyme is only available is prokaryotes. Therefore, only prokaryotes and not eukaryotes show nitrogen fixation.Question:4
Answer:
Ans.Carnivorous plants like Nepenthes and Venus flytrap grow in soil that is deficient in nitrogen. In order to obtain nitrogen, they eat insects trapped by them through their special physical conditions.
Question:5
Answer:
Monotropa is a parasitic plant which lacks chlorophyll. It grows on other plants and depends on its host plant for nutrition and essential elements.Question:7
Answer:
Azotobacter helps in replenishing the nitrogen element through nitrogen fixation.Question:8
What type of conditions are created by leghaemoglobin in the root nodule of a legume?
Answer:
Nitrogenase is highly sensitive to oxygen and hence require an anaerobic condition to function. Leghaemoglobin acts as an oxygen scavenger and protects the nitrogenase enzyme from oxygen. Thus, creating anaerobic conditions in the root nodules of legumes.Mineral Nutrition Excercise: 1.4
Question:9
What is common to Nepenthes, Utricularia and Drosera with regard to the mode of nutrition?
Answer:
All of these are insectivorous plants.Question:12
Name the macronutrient which is a component of all organic compounds but is not obtained from soil.
Answer:
Carbon is obtained from the atmosphere in the form of CO2.Question:13
Name one non-symbiotic nitrogen fixing prokaryote.
Answer:
Azotobacter is a free-living non-symbiotic nitrogen-fixing prokaryote.Question:16
Excess of Mn in soil leads to deficiency of Ca, Mg and Fe. Justify.
Answer:
The toxicity of manganese occurs when plants absorb manganese in large amounts. This excess of Mn causes a reduction in Iron and Magnesium uptake and Ca translocation in the shoot apex, leading to deficiency in Ca, Mg, and Fe.Short Answer Type Questions:
Question:1
How is Sulphur important for plants? Name the amino acids in which it is present.
Answer:
Sulphur is a vital macronutrient that helps in metabolic processes, growth of plants, in composing enzymes, and nodule formation in legumes. Two amino acids in which it is present are cysteine and methionine.Question:2
How are organisms like Pseudomonas and Thiobacillus of great significance in nitrogen cycle?
Answer:
Pseudomonas and Thiobacillus help in denitrification in the nitrogen cycle. They help in converting nitrate salts present in water and soil into a gaseous form that escapes into the atmosphere.Question:3
Carefully observe the following figure: 
(a) Name the technique shown in the figure and the scientist who demonstrated this technique for the first time.
(b) Name at least three plants for which this technique can be employed for their commercial production.
(c) What is the significance of aerating tube and feeding funnel in this setup
Answer:
(a) The technique is hydroponics which was first demonstrated by Julius Von Sachs.(b) Tomato, brinjal, lettuce.
(c) Aerating tube provides oxygen to the roots growing in the solution and feeding funnel is used to provide nutrients and water into the hydroponic system.
Question:4
Answer:
Nitrogenase is the most crucial enzyme that is required for N2 fixation. Nitrogenase is extremely sensitive to oxygen, and this pink coloured pigment called leghemoglobin acts as an oxygen scavenger and creates an anaerobic condition which is necessary for normal functioning of nitrogenase.
Question:5
Answer:
Critical concentration is the concentration of essential elements below which the growth of the plant is stunted and retarded. Deficient concentration is the inadequate supply of nutrient in plant resulting in deficiency symptoms.For Zn, the critical concentration is 0.5 to 1 per cent while deficient is less than 0.5 per cent.
For Fe, the critical concentration is 3.5-5 per cent while deficient is less than 3.5 per cent.
Question:6
Carnivorous plants exhibit nutritional adaptation: Citing an example explain this fact.
Answer:
Carnivorous plants grow in soil that lacks nitrogen and other important nutrients. In order to fulfill its nutritional requirements, it feeds on insects or protozoans. E.g. Venus Fly Trap, Utricularia, Nepenthes etc.In a pitcher plant, its leaf is modified into a pitcher with lids. The inner wall of the leaf has suckers to absorb body fluid from the insects that are trapped.
Question:7
Answer:
The plant can tolerate a specific number of micronutrients only. Even a slightly lesser amount or more of it can cause deficiency or toxicity. It is generally observed that the toxicity of one element can lead to a deficiency of others. For example, in the case of toxicity of manganese, elements like calcium, nitrogen, iron become deficient because when manganese is stored in excess by plants, the calcium is translocated to the shoot apex and deficiency of elements like Magnesium, Iron, and Nitrogen are induced. In such cases, farmers should use these nutrients in their limited concentration as prescribed to prevent any deficiency or excessive intake.
Long Answer Type Questions:
Question:1
It is observed that deficiency of a particular element showed its symptoms initially in older leaves and then in younger leaves.
(a) Does it indicate that the element is actively mobilized or relatively immobile?
(b) Name two elements that are highly mobile and two which are relatively immobile.
(c) How is the aspect of the mobility of elements important to horticulture and agriculture?
Answer:
(a) It indicates that elements are actively mobilized as elements that are actively mobile show deficiency in older leaves before moving to younger leaves.(b) Nitrogen, potassium, and magnesium are highly mobile elements, while calcium and sulfur are relatively immobile elements.
(c) The aspect of the mobility of elements plays a very important role in horticulture and agriculture because with the prevalence of mobility and immobility of elements in older or younger parts of a plant, agriculturalists or horticulturalists can make out deficiencies of elements, and they will be in a better position to provide the required amount of elements as a corrective measure.
Question:2
We find that Rhizobium forms nodules on the roots of leguminous plants. Also, Frankia another microbe forms nitrogen-fixing nodules on the roots of non-leguminous plant Alnus.
(a) Can we artificially induce the property of nitrogen fixation in a plant-leguminous or non–leguminous?
(b) What kind of relationship is observed between mycorrhiza and pine trees?
(c) Is it necessary for a microbe to be in close association with a plant to provide mineral nutrition? Explain with the help of one example.
Answer:
(a) Scientists have tried to induce the property of nitrogen fixation in leguminous and non- leguminous plants through genetic engineering by transforming the nitrogen fixation genes from the bacteria into the plants. But the experiments have shown an exceptionally low success rate, and no viable alternative to natural nitrogen fixation is available.(b) It is a mutual or symbiotic relationship.
(c) Yes, it is necessary for a microbe to be in close association with a plant to provide mineral nutrition. For example, we can illustrate the example of the symbiotic relationship between Rhizobium and leguminous plants. Rhizobium is a bacterium which is found in the root nodules of leguminous plants. The root provides shelter and food to the bacterium, and in return, the bacterium helps in nitrogen fixation in soil.
Question:3
Answer:
Any element that fulfils the essentiality criteria is called an essential element for plants. Some of the various criteria for the essentiality of an element are –(a) The element must be particularly important for facilitating normal growth and reproduction of the plant.
(b) The requirement of the element must be specific, and it should not be replaceable by any other element.
(c) Directly involvement of the element in metabolism in the plant should be present.Minerals are divided into two categories, viz. macronutrients and micronutrients on the basis of the amount in which minerals are needed.
Macronutrients: Elements that are present in large amounts, that is >10 m mole per kg of dry matter,are macronutrients. Examples include carbon, oxygen, hydrogen, nitrogen, etc.
Micronutrients: Elements that are present in small amounts, that is < 10 m mole per kg of dry matter,are micronutrients. Examples include iron, calcium, magnesium, etc.
Question:4
Answer:
Essential elements can be classified into four categories on basis of their functions –(a) As components of biomolecules: These elements form the structural elements of cells.Examples: carbon, oxygen, hydrogen, and nitrogen.
(b) As elements in energy-related compounds: Magnesium in chlorophyll and phosphorus in ATP helps in the photosynthesis process and other metabolic activities that require energy.
(c) Elements that facilitate activation of enzymes like magnesium and zinc.
(d) Elements that can alter or influence osmotic pressure in the cells like potassium.
Question:5
Answer:
A plant can tolerate a specific amount of nutrients only. Even a slightly lesser amount or more of it can cause deficiency or toxicity. It is generally observed that the toxicity of one element can lead to a deficiency of others. For example, in the case of toxicity of manganese, elements like calcium, nitrogen, iron become deficient because when manganese is stored in excess by plants, the calcium is translocated to the shoot apex and deficiency of elements like Magnesium, Iron, and Nitrogen are induced leading to stunted growth or retarded growth of the plant. In such cases, farmers should use these nutrients in their limited concentration as prescribed to prevent any deficiency or excessive intake. Thus, excess of nutrients is never beneficial but harmful for plants.
Question:6
Answer:
(a) Rhizobium bacteria comes into contact with a susceptible root hair and begin to colonize the area of the roots.
(b) The root hairs curl up after being invaded by the bacteria.
(c) The infected thread formed in the roots carries the bacteria into the cortical tissue of the roots.The bacteria modify itself to Bacteroides that is rod-shaped, and as a result, the cortex and pericycle cells present in the roots divide.
(d) Division of the two cells in the cortex leads to the formation of nodules.
(e) A nodule is matured when it forms vascular tissues in continuation with the vascular tissues in the roots.Importance of
Leghaemoglobin: Nitrogenase is the most crucial enzyme that is required for N2 fixation. Nitrogenase is highly sensitive to oxygen, and this pink coloured pigment called leghaemoglobin acts as an oxygen scavenger and creates an anaerobic condition which is
necessary for normal functioning of nitrogenase.
Question:7
Answer:
Biochemical events occurring in the root nodule of a pulse plant are –A) Rhizobium bacteria comes into contact with a susceptible root hair and begin to colonize the area of the roots.
B) The root hairs curl up after being invaded by the bacteria.
C) The infected thread formed in the roots carries the bacteria into the cortical tissue of the roots.The bacteria modify itself to Bacteroides that is rod-shaped, and as a result, the cortex and pericycle cells present in the roots divide.
D) Division of the two cells in the cortex leads to the formation of nodules.
E) A nodule is matured when it forms vascular tissues in continuation with the vascular tissues in the roots. Nitrogenase and leghaemoglobin present in the root nodules catalyze the conversion process in which atmospheric nitrogen is converted into ammonia. Ammonia is the end product of this fixation.
Equation: N2 + 8e- + 8H- + 16ATP
Fate of Ammonia: Ammonia that is produced is converted into ammonium ion, which can be assimilated by plants. But since the ammonium ions are very toxic and should not be accumulated in plants, they get converted into amino acids through ransamination and reductive amination.
Question:8
Answer:
Hydroponics has been sown to be a successful technique for growing of plants, yet most of the crops are still grown on land because of the limitations that the technique poses:a) Hydroponics is still used at experimental stages, and more developments are required before it can be used on a greater scale.
b) The initial cost of setting up the technique is extremely high. Therefore, it is not commercially viable.
c) Maintaining a high level of sterilization while growing crops is a very big problem.
d) Plants that grow through this method need nutrients and water in very frequent intervals which is rather time-consuming and problematic.
e) Since plants are grown in a laboratory, they are highly susceptible to environmental conditions.
Also, check NCERT Class 11 Biology Solutions of other chapters.
More About NCERT Exemplar Class 11 Biology Chapter12
Mineral nutrition is essential for all living beings to be it plants or animals. This chapter elaborates on the mineral nutrition required by plants to regulate their functioning. In the absence of these essential minerals, the plant is unable to carry out a normal cycle.
NCERT Exemplar Class 11 Biology solutions chapter 12 will give students a broader perspective of this NCERT chapter. However, some elements need to be inadequate proportion- neither too less nor too more. Deficiency of sodium, potassium and magnesium can cause disease in the plant, and their excess is toxic for the plant.
Plants also exhibit certain deficiency symptoms like deformation, delay in flowering, necrosis, chlorosis, inhibition of cell division. These are caused due to deficiency of one or more elements.
Nitrogen fixation is responsible for the formation of root nodules. Nitrogen fixation is a process in which nitrogen is converted into ammonia by rhizobium bacteria. Root nodules are visible on the roots of a soya bean plant.
All of which are given in detail in the NCERT Exemplar Class 11 Biology Solutions Chapter 12. By utilising the NCERT Exemplar Class 11 Biology chapter 12 solutions PDF Download function, students can make learning even more convenient as they will get access to quality study material.
Main Subtopics of NCERT Exemplar Class 11 Biology Solutions Chapter 12 Mineral Nutrition:
· Methods to study mineral requirements of plants
· Essential mineral elements
· Criteria for essentiality
· Role of macro and micronutrients
· Deficiency symptoms of essential elements
· Toxicity of micronutrients
· Mechanism of absorption of elements
· Translocation of solutes
· Soil as a reservoir of essential elements
· Metabolism of nitrogen
· Nitrogen cycle
· Biological nitrogen fixation
NCERT Exemplar Class 11 Biology Solutions Chapter-Wise:
What will students learn from NCERT Exemplar Class 11 Biology Solutions Chapter 12 Mineral Nutrition?
NCERT Exemplar Class 11 Biology chapter 12 solutions covers the concept of mineral nutrients required by the plants. This is beneficial for students who are interested in the study of plants that is botany or is inclined towards agriculture. Not just adequate elements but also techniques of growing plants, deficiency symptoms are explained in NCERT Exemplar Class 11 Biology solutions chapter 12.
Do you know that there is a hydrogen cycle that takes place in the plants? The term refers to the conversion of atmospheric nitrogen into compounds that are absorbed by the plants and then are returned to the atmosphere. Students will learn about these aspects, as well.
Important topics of NCERT Exemplar Class 11 Biology Solutions Chapter 12
- Class 11 Biology NCERT Exemplar solutions chapter 12 has explained that Mineral requirements of plants, essential mineral elements, criteria for being essential, the role of nutrients, deficiency symptoms, the mechanism for absorption, soil as a reservoir for nutrients and nitrogen cycle are important topics which students should pay extra attention to.
- NCERT Exemplar Class 11 Biology solutions chapter 12 also includes the process of hydroponics that is the technique of growing plants in a nutrient solution in the absolute absence of soil. However, soil acts as a reservoir of essential elements for plants.
- Once the nutrients are absorbed by the roots and are transported to the leaves, the process of photosynthesis begins.
- After the food preparation is done by the leaves, the translocation of solutes takes place. Translocation is the movement of solutes from leaves to non-photosynthetic parts of the plant.
NCERT Exemplar Class 11 Biology solutions chapter 12 is important for anyone who is wishing to pursue biology or any of its branches in further studies.
NCERT Exemplar Class 11 Solutions for Other Subjects:
| NCERT Exemplar Class 11 Mathematics Solutions |
| NCERT Exemplar Class 11 Chemistry Solutions |
| NCERT Exemplar Class 11 Physics Solutions |
Check Chapter-Wise Solutions of Questions Given in Book:
Chapter 1 | |
Chapter 2 | |
Chapter 3 | |
Chapter 4 | |
Chapter 5 | |
Chapter 6 | |
Chapter 7 | |
Chapter 8 | |
Chapter 9 | |
Chapter 10 | |
Chapter 11 | |
Chapter 12 | |
Chapter 13 | |
Chapter 14 | |
Chapter 15 | |
Chapter 16 | |
Chapter 17 | |
Chapter 18 | |
Chapter 19 | |
Chapter 20 | |
Chapter 21 | |
Chapter 22 |
Also, Read NCERT Solution subject wise
- NCERT Solutions for Class 11 Maths
- NCERT Solutions for Class 11 Physics
- NCERT Solutions for Class 11 Chemistry
Must Read NCERT Notes subject wise
- NCERT Notes for Class 11 Maths
- NCERT Notes for Class 11 Physics
- NCERT Notes for Class 11 Chemistry
- NCERT Notes for Class 11 Biology
Also Check NCERT Books and NCERT Syllabus here
- NCERT Books Class 11 Biology
- NCERT Syllabus Class 11 Biology
- NCERT Books Class 11
- NCERT Syllabus Class 11
Frequently Asked Question (FAQs) - NCERT Exemplar Class 11 Biology Solutions Chapter 12 Mineral Nutrition
Question: Are these solutions in PDF format?
Answer:
Yes, the NCERT exemplar Class 11 Biology solutions chapter 12 pdf download function can be used to download the NCERT Exemplar Class 11 Biology Solutions Chapter 12in a PDF format.
Question: Is this chapter crucial for the entrance exam?
Answer:
Yes, the mineral nutrition chapter is the one from which questions are asked in every medical entrance exam.
Question: Are these solutions in simple language?
Answer:
Yes, we have made sure that all the answers should be in the simplest language for better retention.
Question: How many questions are solved in this chapter?
Answer:
We have covered all 10 questions given in the main exercise in complete detail in NCERT Exemplar Class 11 Biology solutions chapter 12.
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