NCERT Class 11 Biology Mineral Nutrition Important Notes

Read and download free pdf of NCERT Class 11 Biology Mineral Nutrition Important Notes. Students and teachers of Class 11 Biology can get free advanced study material, revision notes, sure shot questions and answers for Class 11 Biology prepared as per the latest syllabus and examination guidelines in your school. Class 11 students should download this study material which will give them more knowledge for all chapters in Biology and all important topics which are scoring and can get you more marks. Students should also download free pdf of Chapter wise Notes for Class 11 Biology prepared by school teachers as per the latest NCERT, CBSE, KVS books and syllabus issued this year and also download free worksheets and question papers available here to get higher scores in school exams and tests, also click here for more Study Material for Class 11 Biology

Study Material for Class 11 Biology Chapter 12 Mineral Nutrition

Class 11 Biology students should refer to the following Pdf for Chapter 12 Mineral Nutrition in Class 11. These notes and test paper with questions and answers for Class 11 Biology will be very useful for exams and help you to score good marks

Class 11 Biology Chapter 12 Mineral Nutrition

Criteria for Essentiality

• The element is absolutely necessary for supporting normal growth and reproduction.

• In the absence of essential elements, plants cannot complete their life cycle or set the seeds.

• The essential element must be specific and is not replaceable by another element.

• The element must be directly involved in metabolism. 

Types of Essential Elements:

There are 17 essential elements in plants. Additionally, some other elements; like sodium, silicon, cobalt and selenium are required by higher plants. There are two types of essential elements, viz. macronutrients and micronutrients.

Macronutrients: Elements which are present in large amounts in plant tissues are called macronutrients. They are in excess of 10 mmole per kg of dry matter. Carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur, potassium, calcium and magnesium are the macronutrients.

Micronutrients: Elements which are present in small amounts, i.e. less than 10 mmole per kg of dry matter are called micronutrients. Iron, manganese, copper, molybdenum, zinc, copper, boron, chlorine and nickel are the micronutrients.

Categories of Essential Elements:

a. As components of biomolecules, e.g. carbon, hydrogen, oxygen and nitrogen. These are structural elements of cells.

b. As components of energy-related chemical compounds, e.g. magnesium in chlorophyll and phosphorous in ATP.

c. Elements which activate or inhibit enzymes, e.g. Mg2+ activates RUBISCO and phosphenol pyruvate carboxylase. Similarly, Zn2+ activates alcohol dehydrogenase.

d. Elements which alter osmotic potential of a cell, e.g. potassium plays an important role in opening and closing of stomata. 

Role of Macro- and Micro-nutrients:

Nitrogen: Nitrogen is the mineral which is required by plants in the greatest amount. Nitrogen is mainly absorbed as NO3 , but some amounts are also taken up as NO4+ or NH4+. Nitrogen is one of the major constituents of protein, nucleic acids, vitamins and hormones.

Phosphorous: This is absorbed by plants in the form of phosphate ions; either as H2PO4 or HPO4 . Phosphorous is a constituent of cell membranes, some proteins, nucleic acids and nucleotides. Phosphorous is also required for all phosphorylation reactions.

Potassium: Potassium is absorbed as potassium ion (K+). This is required in more quantities by the meristematic tissues. Potassium helps in maintaining an anion-cation balance in cells. Potassium is involved in protein synthesis, opening and closing of stomata, activation of enzymes and maintenance of cell turgidity.

Calcium: Calcium is absorbed in the form of calcium ions (Ca2+). Calcium is required by meristematic tissues and differentiating tissues. Calcium is utilised in the synthesis of cell wall. Calcium is also required for the formation of mitotic spindle. Certain enzymes are activated by calcium.

Magnesium: Magnesium is absorbed in the form of magnesium ions (Mg2+). Magnesium activates the enzymes of respiration and photosynthesis. Magnesium is involved in the synthesis of DNA and RNA. It is a constituent of the ring structure of chlorophyll. It also helps in maintaining the ribosome structure.

Sulphur: Sulphur is absorbed in the form of sulphate ion (SO42 –). Sulphur is present in two amino acids; cysteine and mthionine. Sulphur is the main component of several coenzymes, vitamins and ferredoxin.

Iron: Iron is absorbed in the form of ferric ions (Fe+3). Iron is the micronutrient which is required in the largest amount. Iron is an important component of proteins which are involved in electron transfer chain. Iron plays an important role in the formation of chlorophyll.

Manganese: Manganese is absorbed in the form of manganous ions (Mn+2). Manganese activates many enzymes which are involved in photosynthesis, respiration and nitrogen metabolism. Splitting of water molecule during photosynthesis is facilitated by manganese.

Zinc: Zinc is absorbed in the form of zinc ions (Zn+2). Zinc activates various enzymes; like carboxylase. Zinc is required in the synthesis of auxin.

Copper: Copper is absorbed in the form of cupric ions (Cu+2). Copper is essential for overall metabolism in plants. Copper is associated with certain enzymes in redox reactions.

Boron: Boron is absorbed as BO33 – or B4O72 –.Boron is required for uptake and utilization of calcium, membrane functioning, pollen germination, cell elongation, cell differentiation and carbohydrate translocation.

Molybdenum: Molybdenum is absorbed in the form of molybdate ions (MoO22+). Molybdenum is a component of various enzymes; like nitrogenase and nitrate reductase.

Chlorine: Chlorine is absorbed in the form of chloride ion. Along with Na+ and K+, chlorine helps in determining solute concentration and in anion-cation balance. Chlorine also plays an important role in splitting of water.

Deficiency Symptoms of Essential Elements

There are different symptoms for deficiency of different elements. When a deficient mineral is provided to the plant, the symptoms disappear. But if the deficiency continues, it may lead to the death of the plant.

Appearance of deficiency also depends on the mobility of the element in the plant. Some elements are actively mobilized in plants and are exported to young developing tissues. Deficiency of such elements first appears in the older tissues. For example; the deficiency symptoms of nitrogen, potassium and magnesium are first seen in the senescent leaves. This happens because these elements are mobilized to younger leaves.

Some elements are relatively immobile in plants. These elements are not transported out of the mature organs. Deficiency of such elements first appears in younger parts of the plant, e.g. sulphur and calcium.

Some deficiency symptoms in plants are; chlorosis, necrosis, stunted plant growth, premature fall of leaves and buds and inhibition of cell division.

Chlorosis: Loss of chlorophyll is called chlorosis. This results in yellowing of leaves. Chlorosis is caused by the deficiency of N, K, Mg, S, Fe, Mn, Zn and Mo.

Necrosis: Death of tissue; particularly leaf tissue; is called necrosis. Necrosis is caused by the deficiency of Ca, Mg, Cu and K.

Deficiency of N, K, S and Mo causes stunted growth because of inhibition of cell division. Deficiency of N, S and Mo delays flowering.

Toxicity of Micronutrients

If a mineral ion concentration in tissues reaches to a level that it reduces the dry weight of tissues by about 10%, the mineral then becomes toxic. It is difficult to identify the symptoms of toxicity. Sometimes, excess of an element may inhibit the uptake of another element. For example; the symptom of manganese toxicity is the appearance of brown spots surrounded by chlorotic veins. Manganese competes with iron and magnesium for uptake. Manganese also inhibits calcium translocation in shoot apex. Hence, excess of manganese results in deficiency of iron, magnesium and calcium. So, the apparent symptoms of manganese toxicity are in fact the deficiency symptoms of iron, magnesium and calcium.

MECHANISM OF ABSORPTION OF ELEMENTS

Absorption of minerals takes place in two main phases. In the first phase, passive absorption takes place through apoplast pathway. In the second phase, absorption takes place through symplast pathway. The first phase involves passive transport (facilitated diffusion), while the second phase involves active transport. After that, minerals are transported through xylem.

NITROGEN CYCLE

Nitrogen is available in limited amount in soil. Plants have to compete with microbes for this form of nitrogen. Hence, nitrogen is a limiting nutrient for plants.

Lightning and ultraviolet radiations provide energy to convert gaseous nitrogen into oxides of nitrogen (NO, NO2 and N2O). Atmospheric nitrogen oxides also come from industrial combustions, forest fires, automobile exhausts and power stations.

Decomposition of organic nitrogen of dead plants and animals leads to the formation of ammonia. This process is called ammonificaiton. Most of this ammonia is converted into nitrate by soil bacteria, while some of the ammonia vaporizes and re-enters the atmosphere.

Conversion of ammonia into nitrate; by soil bacteria takes place in following steps:

NCERT Class 11 Biology Mineral Nutrition Important Notes1

Biological Nitrogen Fixation (BNF): In this process, the atmospheric nitrogen is converted to ammonia by an enzyme called nitrogenase. This can be shown by following equation:

N2 + 6H+ + 6e− → 2NH3

This process is coupled with the hydrolysis of 16 equivalents of ATP. This is also accompanied by the co-formation of one molecule of H2.

In free-living diazotrophs, the nitrogenase-generated ammonium is assimilated into glutamate through the glutamine synthetase or glutamate synthase pathway. Many nitrogen-fixing organisms exist only in anaerobic conditions; because the enzymes responsible for nitrogenase action are highly susceptible to destruction by oxygen.

Symbiotic Biological Fixation of Nitrogen

The plants of the legume family (Fabaceae) are the major contributors towards nitrogen fixation. The root nodules of these plants harbor the Rhizobium bacteria. These bacteria produce nitrogen compounds which help the plant to grow properly. When the plant dies, the fixed nitrogen is released into the soil. Thus nitrogen becomes available for other plants.

NCERT Class 11 Biology Mineral Nutrition Important Notes



NCERT Solution for Class 11 Biology Mineral Nutrition

Question 1: ‘All elements that are present in a plant need not be essential to its survival’. Comment.

Answer: An element should fulfill certain criteria to be categorized as essential element. Otherwise, it cannot be considered as essential elements. Out of the numerous elements present in plants, only 17 are considered as essential elements.

Question 2: Why is purification of water and nutrient salts so important in studies involving mineral nutrition using hydroponics.

Answer: Purification of water and nutrient salt is important to rule out other influencing factors. Use of pure nutrients and water will help in obtaining accurate scientific results.

Question 3: Explain with examples: macronutrients, micronutrients, beneficial nutrients, toxic elements and essential elements.

Answer: Macronutrients: Elements which are present in large amounts in plant tissues are called macronutrients. They are in excess of 10 mmole per kg of dry matter. Carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur, potassium, calcium and magnesium are the macronutrients.

Micronutrients: Elements which are present in small amounts, i.e. less than 10 mmole per kg of dry matter are called micronutrients. Iron, manganese, copper, molybdenum, zinc, copper, boron, chlorine and nickel are the micronutrients.

Beneficial Elements: Apart from the 17 essential elements, many other elements are required by plants. For example; sodium, silicon, cobalt and selenium are required by higher plants.

These are called beneficial elements.

Toxic Elements: If a mineral ion concentration in tissues reaches to a level that it reduces the dry weight of tissues by about 10%, the mineral then becomes toxic. This shows that any element can become toxic if it crosses a certain threshold in plants.

Question 4: Name at least five different deficiency symptoms in plants. Describe them and correlate them with the concerned mineral deficiency.

Answer: Following are the five deficiency symptoms and related minerals:

a. Yellowing of lower leaves: Magnesium deficiency

b. Pale green leaves: Nitrogen deficiency

c. Purple leaf tints with bronze or brown leaf edges: Potassium deficiency

d. Reddish purple undersides of leaves: Phosphorous deficiency

e. White deposits on leaves: Carbon dioxide deficiency 

Question 5: If a plant shows a symptom which could develop due to deficiency of more than one nutrient, how would you find out experimentally, the real deficient mineral element?

Answer: For this, we need to tabulate all the available symptoms in different parts of the plant. Then the symptoms are compared with the symptom table; to arrive at a conclusion about the deficiency of a specific element.

Question 6: Why is that in certain plants deficiency symptoms appear first in younger parts of the plant while in others they do so in mature organs?

Answer: Appearance of deficiency also depends on the mobility of the element in the plant. Some elements are actively mobilized in plants and are exported to young developing tissues. Deficiency of such elements first appears in the older tissues. For example; the deficiency symptoms of nitrogen,

potassium and magnesium are first seen in the senescent leaves. This happens because these elements are mobilized to younger leaves.

Question 7: How are the minerals absorbed by the plants?

Answer: Absorption of minerals takes place in two main phases. In the first phase, passive absorption takes place through apoplast pathway. In the second phase, absorption takes place through symplast pathway. The first phase involves passive transport (facilitated diffusion), while the second phase involves active transport. After that, minerals are transported through xylem.

Question 8: What are the conditions necessary for fixation of atmospheric nitrogen by Rhizobium. What is their role in N2 -fixation?

Answer: Rhizobium bacteria need symbiotic association with legume plants to carry out nitrogen fixation. Root nodules contain the necessary enzymes for nitrogen fixation and thus enable rhizobium to fix nitrogen. The enzyme nitrogenase facilitates the conversion of nitrogen into ammonia which is the first stable product of nitrogen fixation. Ammonia is then converted into glutamic acid. Glutamic acid is then utilised by plants to make amino acids; which are then utilised to make protein.

Question 9: What are the steps involved in formation of a root nodule?

Answer: Development of root nodules happens in following steps:

a. Rhizobium bacteria contact a susceptible root hair and divides near it.

b. Successful infection of the root hair results in curling of the root hair.

c. The infected thread carries the bacteria to the inner cortex. The bacteria get modified into rod-shaped bacteroids and cause inner cortical and pericycle cells to divide. Division and growth of cortical and pericycle cells lead to nodule formation.

d. A mature nodule is complete with vascular tissues. The vascular tissues of the nodule are continuous with those of the root. 

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

(a) Boron deficiency leads to stout axis.

Answer: True

(b) Every mineral element that is present in a cell is needed by the cell.

Answer: Out of all the mineral elements, only 17 are considered as essential elements.

(c) Nitrogen as a nutrient element, is highly immobile in the plants.

Answer: Nitrogen is highly mobile in plants.

(d) It is very easy to establish the essentiality of micronutrients because they are required only in trace quantities.

 

Answer: True

More Study Material

CBSE Class 11 Biology Chapter 12 Mineral Nutrition Study Material

We hope students liked the above Study Material for Chapter 12 Mineral Nutrition designed as per the latest syllabus for Class 11 Biology released by CBSE. Students of Class 11 should download the Study Material in Pdf format, read the notes and related questions and solutions given in above Class 11 Biology Study Material on daily basis. All latest Study Material have been developed for Biology by referring to the most important and regularly asked topics which the students should learn and practice to get better score in school tests and examinations. Studiestoday is the best portal for Class 11 students to get all latest study material free of cost.

Study Material for Biology CBSE Class 11 Chapter 12 Mineral Nutrition

Expert teachers of studiestoday have referred to NCERT book for Class 11 Biology to develop the Biology Class 11 Study Material. If you download Study Material for the above chapter daily, you will get higher and better marks in Class 11 test and exams in the current year as you will be able to have stronger understanding of all concepts. Daily reading of Biology study material will help students to have stronger understanding of all concepts and also make them expert on all critical topics. You can easily download and save all Study Material for Class 11 Biology also from www.studiestoday.com without paying anything in Pdf format. After solving the questions given in the Study Material which have been developed as per latest course books also refer to the NCERT solutions for Class 11 Biology designed by our teachers

Chapter 12 Mineral Nutrition Study Material Biology CBSE Class 11

All Study Material given above for Class 11 Biology have been made as per the latest syllabus and books issued for the current academic year. The students of Class 11 can refer to the answers which have been also provided by our teachers for all Study Material of Biology so that you are able to solve the questions and then compare your answers with the solutions provided by us. We have also provided lot of MCQ questions for Class 11 Biology so that you can solve questions relating to all topics given in each chapter. Also download Class 11 Biology Sample Papers given on studiestoday.

Chapter 12 Mineral Nutrition CBSE Class 11 Study Material Biology

Regular Study Material reading helps to gain more comprehensive understanding of Chapter 12 Mineral Nutrition concepts. Study Material play an important role in developing understanding of Chapter 12 Mineral Nutrition in CBSE Class 11. Students can download and save or print all the Study Material, printable assignments, practice sheets of the above chapter in Class 11 Biology in Pdf format from studiestoday. You can print or read them online on your computer or mobile or any other device. After solving these you should also refer to Class 11 Biology MCQ Test for the same chapter

CBSE Study Material Biology Class 11 Chapter 12 Mineral Nutrition

CBSE Class 11 Biology best textbooks have been used for writing the problems given in the above Study Material. If you have tests coming up then you should revise all concepts relating to Chapter 12 Mineral Nutrition and then take out print of the above Study Material and attempt all problems. We have also provided a lot of other Study Material for Class 11 Biology which you can use to further make yourself better in Biology.

How to download CBSE Class 11 Biology Chapter 12 Mineral Nutrition study material

You can download free study material for Class 11 Biology Chapter 12 Mineral Nutrition for latest academic session from StudiesToday.com

Can I download study material for Chapter 12 Mineral Nutrition Class 11 Biology in Pdf format

Yes, you can click on the link above and download PDFs for Class 11 Biology Chapter 12 Mineral Nutrition easily for regular use

Is the study material for Chapter 12 Mineral Nutrition Class 11 Biology for the latest CBSE academic session

Yes, the study material given here for Class 11 Biology Chapter 12 Mineral Nutrition is for current CBSE session

Can I download Chapter 12 Mineral Nutrition Class 11 Biology study notes in pdf

You, just click the link above and save Class 11 study material for Biology Chapter 12 Mineral Nutrition in Pdf

Is there any charge for Class 11 Biology Chapter 12 Mineral Nutrition concepts and study material

All study maetrial for CBSE Class 11 Biology Chapter 12 Mineral Nutrition is free

Tell me the best website to get study material for Chapter 12 Mineral Nutrition Class 11 Biology

www.studiestoday.com is the best portal for Chapter 12 Mineral Nutrition Biology Class 11 study material

How to get topic-wise study material for Class 11 Biology Chapter 12 Mineral Nutrition

Visit www.studiestoday.com for best study material for Class 11 Biology Chapter 12 Mineral Nutrition

How to print Chapter 12 Mineral Nutrition Class 11 Biology study notes as per CBSE syllabus

All study material for various topics of Class 11 Biology Chapter 12 Mineral Nutrition as per latest CBSE syllabus is avaiable here