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NCERT Exemplar Class 11 Biology Solutions Chapter 12: The chapter provides a deep understanding of important nutrients required for plant growth and their role in metabolic processes. The Solutions are formulated to help students understand key concepts related to micronutrients, macronutrients, deficiency symptoms, etc. The questions contain well-structured answers, ensuring a proper understanding of the chapter. Solving these MCQs will strengthen their understanding of major processes like nutrient cycles. The NCERT exemplar solutions provide a variety of objective-type questions and their answers to test the application of concepts in real-life scenarios.
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Studying the MCQs regularly enhances analytical thinking and accuracy exams by consistently working through these resources. Students can ensure a strong understanding of Mineral Nutrition, and improve their overall biology scores. These exemplar solutions give an extra edge to the students while attempting the problems given in the NCERT Class 11 Biology Book.
The solved exemplar questions are given below-
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 the soil.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.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.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 deficiencies would show such symptoms?
(a) Sulphur
(b) Magnesium
(c) Nitrogen
(d) Potassium
Answer:
The answer is the option (a) SulphurQuestion: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 aboveQuestion:5
Reactions 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 option (d) bacteria carrying out these steps are usually photoautotrophs.s(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 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 |
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 option (d) water or soil without essential nutrients.Question:1
Name a plant, which accumulates silicon.
Answer:
Oryza sativa (Rice).Question:2
Answer:
Mycorrhiza is a symbiotic or mutualistic association between fungi and the roots of vascular plants. In this association, the roots provide shelter to the fungus, and the fungus helps the roots in the intake of minerals, water, and other nutrients.Question:3
Nitrogen fixation is shown by prokaryotes and not eukaryotes. Comments?
Answer:
Nitrogenase is the enzyme which is required for nitrogen fixation. This enzyme is only available in prokaryotes. Therefore, only prokaryotes and not eukaryotes show nitrogen fixation.Question:4
Answer:
Carnivorous plants like Nepenthes and Venus flytraps grow in soil that is deficient in nitrogen. 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 requires 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 about 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.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, 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 the 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 the aerating tube and feeding funnel in this setup
Answer:
(a) The technique is hydroponics which was first demonstrated by Julius Von Sachs.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 the 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 nutrients in plants resulting in deficiency symptoms.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. To fulfil its nutritional requirements, it feeds on insects or protozoans. E.g. Venus Fly Trap, Utricularia, Nepenthes etc.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, and 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.
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.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 the 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. However the experiments have shown an exceptionally low success rate, and no viable alternative to natural nitrogen fixation is available.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 –Question:4
Answer:
Essential elements can be classified into four categories based on their functions –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, and 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 nutrients are never beneficial but harmful to plants.
Question:6
Answer:
Question:7
Answer:
Biochemical events occurring in the root nodule of a pulse plant are –Question:8
Answer:
Hydroponics has been seen to be a successful technique for growing plants, yet most of the crops are still grown on land because of the limitations that the technique poses: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 |
Understanding the most important questions from this chapter is crucial because Mineral Nutrition is a frequently tested topic in NEET, covering essential elements, deficiency symptoms, absorption mechanisms, and nitrogen fixation. Practising previous years’ questions (PYQs) helps students identify the exam pattern and focus on high-yield concepts, ensuring better preparation and confidence during the exam.
5 NEET PYQs from Mineral Nutrition:
Q1. The oxygen evolved during photosynthesis comes from water molecules. Which one of the following pairs of elements is involved in this reaction?
A. Manganese and potassium
B. Manganese and chlorine
C. Magnesium and chlorine
D. Magnesium and molybdenum
Answer:
The oxygen evolved during photosynthesis is produced when water molecules are split in the oxygen-evolving complex of Photosystem II. This complex contains manganese ions and is associated with chloride ions, both of which are essential for the catalytic splitting of water to release oxygen gas during the light-dependent reactions of photosynthesis68. Hence, the correct option is B. Manganese and chlorine.
Q2. During biological nitrogen fixation, inactivation of nitrogenase by oxygen poisoning is prevented by
A. xanthophyll
B. cytochrome
C. carotene
D. leghaemoglobin
Answer:
During biological nitrogen fixation, the enzyme nitrogenase is highly sensitive to oxygen and can be inactivated by it. In leguminous plants, leghaemoglobin acts as an oxygen scavenger in root nodules, maintaining a low oxygen concentration to protect nitrogenase and allow efficient nitrogen fixation.
Hence, the correct option is D. leghaemoglobin.
Q3. Deficiency symptoms of nitrogen and potassium are visible first in
A. buds
B. roots
C. young leaves
D. senescent leaves
Answer:
Nitrogen and potassium are mobile nutrients in plants. When there is a deficiency, these nutrients are translocated from older tissues to younger growing parts, so the deficiency symptoms first appear in the older, senescent leaves.
Hence, the correct option is D. senescent leaves.
Q4. Specialised cells for fixing atmospheric nitrogen in Nostoc are
A. akinetes
B. nodules
C. hormogonia
D. heterocysts
Answer:
In Nostoc, specialized thick-walled cells called heterocysts are responsible for fixing atmospheric nitrogen. These cells provide an anaerobic environment necessary for the functioning of nitrogenase, the enzyme complex involved in nitrogen fixation.
Hence, the correct option is D. heterocysts.
Q5. Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas (N₂) to the atmosphere?
A. Enteric fermentation in cattle and nitrogen fixation by Rhizobium in root nodules of legumes
B. Anaerobic ammonium oxidation and denitrification
C. Decomposition of organic nitrogen and conversion of dinitrogen to ammonium compounds
D. Aerobic nitrate oxidation and nitrite reduction
Answer:
The two distinct microbial processes responsible for the release of fixed nitrogen as dinitrogen gas (N₂) to the atmosphere are anaerobic ammonium oxidation (anammox) and denitrification. Both processes convert fixed forms of nitrogen back into gaseous nitrogen, completing the nitrogen cycle.
Hence, the correct option is B. Anaerobic ammonium oxidation and denitrification.
Also, read the NCERT Solution subject-wise
A methodical approach to question-solving is crucial since this chapter contains both factual and conceptual material, and students need to differentiate between various components, their functions, and their deficiency symptoms. By adopting a systematic approach, students can solve both direct and application-based questions with confidence, which is crucial for competitive exams such as NEET.
Must Read NCERT Notes subject-wise
Exceeding the NCERT is required for NEET as the examination frequently incorporates application-based and tricky questions requiring a profound understanding beyond what is offered in the textbook. Practice from reference books, last year's questions, and advanced MCQs guarantees extensive coverage and enhanced problem-solving ability.
Concept / Topic | NCERT | NEET |
---|---|---|
Essential and Non‑essential Elements | ✅ | ✅ |
Criteria for Essentiality | ✅ | ✅ |
Macro and Micronutrients (with examples) | ✅ | ✅ |
Deficiency Symptoms and Toxicity | ✅ | ✅ |
Mechanism of Absorption (Active/Passive) | ✅ | ✅ |
Translocation of Solutes | ✅ | ✅ |
Soil as a Reservoir of Nutrients | ✅ | ✅ |
Nitrogen Cycle and Nitrogen Fixation | ✅ | ✅ |
Hydroponics and Its Applications | ✅ | ✅ |
Mycorrhiza and Plant Nutrition | ⬜ | ✅ |
Phytoremediation of Heavy Metals | ⬜ | ✅ |
Mineral Uptake Transporters (Channel vs. Carrier Proteins) | ⬜ | ✅ |
Root Nodule Formation and Signaling Pathways | ⬜ | ✅ |
Also, check the NCERT Books and the NCERT Syllabus here
The links of the solutions of all chapters are given below:
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 12 in a PDF format.
Yes, we have made sure that all the answers should be in the simplest language for better retention.
Yes, the mineral nutrition chapter is the one from which questions are asked in every medical entrance exam.
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