NCERT Exemplar Class 11 Biology Solutions Chapter 12 Mineral Nutrition

Access NCERT Exemplar Class 11 Biology Solutions Chapter 12 (MCQs)

Given below are the different forms of questions, such as MCQs, short, and long answer types. The NCERT Exemplar Class 11 Biology Chapter 12 helps students test their understanding in various ways and prepare better for exams.

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 option (b), changing the chemistry of the soil.

Explanation: 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 the plant remains in the vegetative phase.
(d) None of the above

Answer:

The answer is 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 the plant remains in the vegetative phase.
(d) None of the above

Answer:

The answer is 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 deficiencies would show such symptoms?
(a) Sulphur
(b) Magnesium
(c) Nitrogen
(d) Potassium

Answer:

The answer is option (a) Sulphur

Explanation: 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 the shoot apex is inhibited
(b) Deficiency in both Iron and Nitrogen is induced
(c) Appearance of a brown spot surrounded by chlorotic veins
(d) None of the above

Answer:

The answer is option (d) None of the above

Explanation: Toxicity of manganese occurs when plants absorb manganese in large amounts. This high intake causes a deficiency in Iron and Nitrogen, Ca translocation in the shoot apex, and brown spots surrounded by chlorotic veins.

Question:5

Reactions carried out by N₂-fixing microbes include
(a)2NH₃+3O₂→2NO₂+2H+2H₂O

(b)2NO₂⁻+O₂→2NO₃^-
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.

Explanation: Bacteria carrying out nitrogen fixation are chemoautotrophs and not photoautotrophs.

Question 6:

About the Biological Nitrogen Fixation by Rhizobium in association with soybean, one of the following statements does not hold.

(a) Nitrogenase may require oxygen for its functioning.
(b) Nitrogenase is a 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 option (a) Nitrogenase may require oxygen for its functioning.

Explanation: 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

Match the element with its associated functions/roles and choose the correct option among the given below

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)

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.

Explanation: Plants cannot grow in water or soil without essential nutrients because a lack of nutrients will

lead to no growth.

Find the Mineral Nutrition Class 11 NCERT Exemplar- Very Short Answer Questions

Question:1

Name a plant that accumulates silicon.

Answer:

Oryza sativa (Rice).

Question:2

Mycorrhiza is a mutualistic association. How do the organisms involved in this association gain from each other?

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 that is required for nitrogen fixation. This enzyme is only available in prokaryotes. Therefore, only prokaryotes and not eukaryotes show nitrogen fixation.

Question:4

Carnivorous plants like Nepenthes and Venus flytraps have nutritional adaptations. Which nutrient do they especially obtain, and from where?

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

Think of a plant that lacks chlorophyll. From where will it obtain nutrition? Give an example of such a type of plant.

Answer:

Monotropa is a parasitic plant that lacks chlorophyll. It grows on other plants and depends on its host plant for nutrition and essential elements.

Question:6

Name an insectivorous angiosperm.

Answer:

Utricularia, also known as bladderworts.

Question:7

A farmer adds Azotobacter culture to the soil before sowing maize. Which mineral element is being replenished?

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.

Question:9

What is common to Nepenthes, Utricularia, and Drosera about the mode of nutrition?

Answer:

All of these are insectivorous plants.

Question:10

Plants with zinc deficiency show reduced biosynthesis of _________

Answer:

Auxin (IAA).

Question:11

Yellowish edges appear in leaves deficient in_______

Answer:

Potassium

Question:12

Name the macronutrient that 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:14

Rice fields produce an important greenhouse gas. Name it.

Answer:

CH₄ Methane

Question:15

Complete the equation for reductive amination
?+NH₄+NADPH→?Glutamate+H₂O+NADP

Answer:

α−Kentoglutaricacid+NH₄+NADPH→Glutamatedehydrogenase+H₂O+NADP

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.

Discover NCERT Exemplar Class 11 Biology Solutions Chapter 12- Short Answer 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, 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.

(b) Tomato, brinjal, lettuce.

(c) The aerating tube provides oxygen to the roots growing in the solution, and the feeding funnel is used to provide nutrients and water to the hydroponic system.

Question:4

Name the most crucial enzyme found in root nodules for N₂ fixation. Does it require a special pink-coloured pigment for its functioning? Elaborate.

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

How are the terms ‘critical concentration’ and ‘deficient’ different from each other in terms of the concentration of an essential element in plants? Can you find the values of ‘critical concentration’ and ‘deficiency’ for minerals — Fe & Zn?

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.

For Zn: Critical concentration is 20–100 ppm.

For Fe: Critical concentration is 50–250 ppm

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.

In a pitcher plant, its leaf is modified into a pitcher with a lid. The inner wall of the leaf has suckers to absorb body fluid from the insects that are trapped.

Question:7

A farmer adds/ supplies Na, Ca, Mg, and Fe regularly to his field, and yet he observes that the plants show a deficiency of Ca, Mg, and Fe. Give a valid reason and suggest a way to help the farmer improve the growth of plants.

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 is induced. In such cases, farmers should use these nutrients in their limited concentration as prescribed to prevent any deficiency or excessive intake.

Detailed NCERT Exemplar Class 11 Biology Solutions Chapter 12

Question:1

It is observed that the efficiency 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 that 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 a 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 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.

(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 that 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

What are the essential elements for plants? Give the criteria of essentiality. How are minerals classified depending upon the amount in which they are needed by the plants?

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) Direct involvement of the element in metabolism in the plant should be present. Minerals are divided into two categories, viz., macronutrients and micronutrients, based on the amount of minerals needed.

Macronutrients: C, H, O, N, P, K, Ca, Mg, S.

Micronutrients: Fe, Zn, Cu, Mn, B, Mo, Cl, Ni.

Question:4

With the help of examples, describe the classification of essential elements based on the function they perform.

Answer:

Essential elements can be classified into four categories based on 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 help in the photosynthesis process and other metabolic activities that require energy.

(c) Elements that facilitate the activation of enzymes, like magnesium and zinc.

(d) Elements that can alter or influence osmotic pressure in the cells, like potassium.

Question:5

We know that plants require nutrients. If we supply these in excess, will it be beneficial to the plants? If yes, how/ If no, why?

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 is 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

Trace the events starting from the coming in contact of Rhizobium with a leguminous root till nodule formation. Add a note on the importance of leg haemoglobin.

Answer:

(a) Rhizobium bacteria come 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 themselves to Bacteroides, which are rod-shaped, and as a result, the cortex and pericycle cells present in the roots divide.

(d) The division of the two cells in the cortex leads to the formation of nodules.

(e) A nodule is mature 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 the normal functioning of nitrogenase.

Question:7

Give the biochemical events occurring in the root nodule of a pulse plant. What is the end product? What is its fate?

Answer:

Biochemical events occurring in the root nodule of a pulse plant are –

A) Rhizobium bacteria come 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 themselves to Bacteroides, which are rod-shaped, and as a result, the cortex and pericycle cells present in the roots divide.

D) The division of the two cells in the cortex leads to the formation of nodules.

E) A nodule is mature 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→ 2NH₃ + H₂ + 16 ADP + 16P_i

Fate of Ammonia: Ammonia that is produced is converted into ammonium ions, which can be assimilated by plants. However, since the ammonium ions are very toxic and should not be accumulated in plants, they get converted into amino acids through transamination and reductive amination.

Question:8

Hydroponics is a successful technique for growing plants. Yet most of the crops are still grown on land. Why?

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:

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 the NCERT Books and the NCERT Syllabus here

• NCERT Books Class 11 Biology

• NCERT Syllabus Class 11 Biology

• NCERT Books Class 11

• NCERT Syllabus Class 11

Approach to Solve Questions of Mineral Nutrition Class 11 NCERT Exemplar

A well-structured approach to question-solving is important since this chapter contains both factual and conceptual parts. By adopting a systematic approach, students can solve both direct and application-based questions with confidence.

• Go through the NCERT chapter carefully to understand the fundamental concepts and definitions.

• Practice diagram and labelling for processes such as nitrogen fixation and nodule formation.

• Try all the questions given in the Mineral Nutrition Class 11 NCERT Exemplar, to improve speed and accuracy..

• Connect the symptoms and functions of nutrients to plant examples in real life for improved retention.

• Review important cycles (e.g., nitrogen cycle) and differences (macro vs. micro nutrients) given in the NCERT Exemplar Class 11 Biology Chapter 12.

Also, read the NCERT Solution subject-wise

• NCERT Solutions for Class 11 Maths

• NCERT Solutions for Class 11 Physics

• NCERT Solutions for Class 11 Chemistry

• NCERT Solutions for Class 11 Biology

Main topics of NCERT Exemplar Class 11 Biology Solutions Chapter 12

This chapter includes many important topics that explain how plants absorb minerals and the nutrients required for their growth and metabolism.

• Essential mineral elements

• Macronutrients and micronutrients

• Deficiency symptoms in plants

• Role of nitrogen in plants

• Nitrogen cycle

• Biological nitrogen fixation

• Methods of absorption of elements

• Translocation of solutes

• Hydroponics and its applications

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

Important Question from Mineral Nutrition Class 11 NCERT Exemplar

Understanding the most important questions from this chapter is important because Mineral Nutrition is a frequently asked topic in NEET. The NCERT Exemplar Class 11 Biology Chapter 12 covers topics like elements, deficiency symptoms, absorption mechanisms, and nitrogen fixation.

Question 1. 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 correct option is B. Manganese and chlorine.
Explanation:

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 photosynthesis.

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

NCERT Exemplar Class 11 Biology Solutions Chapter-Wise

The links to the solutions of all chapters are given below, by which students can start their practice and score better in the exams.