![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/KSEEB-Solutions.png\")
<\/p>\nQuestion 1.
\nName a plant which accumulates silica.
\nAnswer:
\nEquisetum.<\/p>\n
Question 2.
\nMycorrhiza is a mutualistic association. How do the organisms involved in this association gain from each other?
\nAnswer:
\nThe fungus partner gets shelter and food from the plant, while the plant obtains minerals, and water from the fungus.<\/p>\n
<\/p>\n
Question 3.
\nName an insectivorous angiosperm.
\nAnswer:
\nNepenthes (Pitcher Plant).<\/p>\n
Question 4.
\nA farmer adds azotobacter culture to soil before sowing Maize. Which mineral element is being replenished?
\nAnswer:
\nNitrogen.<\/p>\n
Question 5.
\nName the macronutrient which is a component of all organic compounds, but is not obtained from the soil.
\nAnswer:
\nCarbon.<\/p>\n
<\/p>\n
Question 6.
\nName one non-symbiotic nitrogen fixing prokaryote.
\nAnswer:
\nAzotobacter.<\/p>\n
Question 7.
\nRice fields produce an important green house gas. Name it.
\nAnswer:
\nMethane.<\/p>\n
Question 1.
\n\u2018All the elements that are present in a plant, need not be essential to its survival\u2019. Comment.
\nAnswer:
\nA number of elements are found in plants. More than 60 elements have been detected in them. However, all the elements found in plants are not essential for them. The non-essential elements enter plants because of the pathway common with some essential elements, and special conditions of the soil which make them soluble.<\/p>\n
Question2.
\nWhy is it that in certain plants deficiency symptoms appear first in younger parts of the plant while in others they do so in mature organs?
\nAnswer:
\nCertain mineral nutrients are mobile in the plants while others are not. During deficiency, the mobile elements are mobilised from the mature leaves, and transferred to younger leaves. In such cases, the deficiency symptoms appear first in older leaves, e.g., N, P, Mg. Other nutrients are immobile inside the plants. In such cases, the deficiency symptoms appear first in young leaves, e.g., Fe, Ca, S.<\/p>\n
<\/p>\n
Question 3.
\nComplete the equation for reductive amination.
\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-12-Mineral-Nutrition-6.png\")
\n(b) Photo phosphorylation:
\nThe extra energy of ejected electrons during photoexcitation is used for phosphorylation of ‘ADP into ATP Hence it is called photophosphorylation. It is of two types namely,
\n(ii) Cyclic Photo phosphorylation
\n(a) Cyclic Photo phosphorylation :
\n(b) Non-cyclic Photo phosphorylation.<\/p>\n
(b) Non-cyclic Photo phosphorylation: – In PS I the absorbed photons of light excite chlorophyll-a 100 to eject energised electrons which pass through FRS, FD, and finally get locked up with NADP which becomes negatively charged, and partially reduced, while PSI becomes positively charged and unstable.<\/p>\n – At the, same time in PS II, the absorbed photons of light excite chlorophyll a 680 to eject energised electrons which pass through in sequence, pheophytin, PQ, cyto b6<\/sub>, cytf, plastocyanin, and generate ATP. The electrons finally join P.S I to replace its lost electrons and restore its stability. Now P.S II becomes positively charged, and unstable. Meanwhile electrons of photolysed water join with PS II to replace its lost electrons, and restore its stability. Protons join with the already ionised NADP, and complete its reduction to NADPH2<\/sub><\/p>\n DARK REACTION \/ Blackmann\u2019s Reaction \/ Calvin cycle \/ C3<\/sub> Pathway: (1) Carboxylative phase: (CO2<\/sub>\u00a0Fixation):The five carbon ribulose mono phosphates (RUMP) present in stroma, is phosphorylated by ATP to ribulose diphosphate (RUDP). RUDP is the initial CO2<\/sub> acceptor which forms an unstable six carbon compound. It soon splits to form two molecules of a three carbon compound, namely phosphoglyceric acid (PGA), the first stable compound. At a time, six CO2<\/sub> molecules are fixed, which eventually results in the formation of 12 molecules of PGA.<\/p>\n (2) Reduction phase: The 12 PGA are phosphorylated by 12 ATP of assimilatory power to form 12 molecules of DPGA (Diphosphoglyceric acid). They soon loose 12 phosphates to an inorganic source and become reduced by 12 NADPH2<\/sub> of assimilatory power to the form 12 molecules of PGAL (Phosphoglyceraldehyde). PGAL can isomerise into DHAP (Dilhydroxy acetone phosphate) which is a reversible reaction.<\/p>\n (3) Regeneration Phase: Of the 12 Molecules of PGAL, 10 molecules undergo a series of complex reactions to regenerate 6 RUMP.<\/p>\n (4) Glucose Formation: The remaining two molecules (PGAL and DHAP) get condensed by – aldolase to form fructose 1-6 diphosphate. It is later dephosphorylated twice, and isomerised to form glucose.<\/p>\n C2<\/sub>\u00a0Pathway Or Hatch Slack Pathway:<\/p>\n Mechanism:<\/p>\n Photo Respiration: Phosphoglycollic acid is quickly converted into glycolic acid, and transported to peroxisomes. In peroxisome, glycollic acid is oxidised to glyoxylic acid, and is converted into amino acid, ‘glycine.<\/p>\n Glycine enters the mitochondria, and two glycine molecples give rise to one molecule of serine and one molecule of CO2<\/sub> serine is picked up by peroxisomes, and is converted to glyceric acid by series of reactions. Question 5. Question 6. Question 1. Question 2. Free living nitrogen fixers include: Symbiotic nitrogen fixers include:<\/p>\n Biological nitrogen fixation requires the following three biochemical components. \u2022 The leghaemoglobin is a pink colour pigment similar to haemoglobin of vertebrates, and Question 1. Micronutrients : They are essential elements which occur in plants in a concentration of 0.1 mg or below per gm of dry matter, e,g\u201e Mn, Zn, Cu, Mo, Bo.<\/p>\n Beneficial Nutrients : They are non-essential elements which have some specific role in some plants, e.g., Na+<\/sup> in C4<\/sub> plants, Si in grasses.<\/p>\n Toxic Elements : They are non-essential elements which if absorbed reduce plant growth, and yield. Many elements become toxic only after their concentration reaches a particular level, e g., Lead, Aluminium, Mn. Question 2. An element is said to be deficient, if it is present below its critical concentration. Since each element has one or more specific structural or functional role in plants, in the absence of any particular element, the plants show certain morphological\/ observable changes. They are indicative deficiency of a certain element, and are called as deficiency symptoms.<\/p>\n The common deficiency symptoms include : (ii) Necrosis : It refers to the death of tissues (especially of leaves) e.g., Deficiency of elements like calcium, magnesium, copper, potassium.<\/p>\n (iii) Inhibition of Cell. Division : It is caused by deficiency of potassium, nitrogen, and molybdenum.<\/p>\n (iv) Delay in flowering: Deficiency of elements like nitrogen, sulphur, and molybdenum causes delay in flowering.<\/p>\n The deficiency symptoms tend to appear first in the young tissues in the case of elements that are relatively immobile, and are not transported out of the mature organs. e.g., Sulphur, and calcium, which form structural components.<\/p>\n The deficiency symptoms tend to appear first in older tissues, if the elements are actively mobile, they are withdrawn from the senescing organs, and transported to young tissues. e.g., Nitrogen, potassium and magnesium.<\/p>\n Question 3. Root Nodule Formation in a leguminous plant.<\/p>\n 1. Methods’to Study The Mineral Requirements Of Plants.<\/p>\n Julius Van Sachs (I860) demonstrated that plants could be grown to maturity in a defined nutrient solution and in the complete absence of soil. Hydroponics has the following uses :<\/p>\n To achieve optimum growth of plants,<\/p>\n 2. Criteria Of Essentiality Of An Element.<\/p>\n 3. Essential Elements. (i) Macronutrients : Macronutrients are those elements, which are generally present in large amounts in the plant tissues, i.e., in excess of 10 m. mole kg-1<\/sup> of dry matter, e.g., Carbon, hydrogen, oxygen, nitrogen, phosphorus, sulphur, potassium, and magnesium.<\/p>\n (ii) Micronutrients: Micronutrients or trace elements are those elements, which are needed in minute quantities, i.e., 0.1 mg per gram of dry matter. i.e., Boron, copper, iron, manganese, molybdenum, zinc, nickel and chlorine. Some plants also require traces of cobalt, selenium, and silicon.<\/p>\n (B) Essential elements can also be classified into four categories, based on their diverse functions, as given below:<\/p>\n 4. Role Of Macroelements And Their Deficiency Symptoms In Plants:<\/p>\n (A) Nitrogen : Functions: Deficiency symptoms:<\/p>\n (B) Sulphur : Functions: symptoms : (C) Phosphorus: Deficiency Symptoms : (D) Potassium: Functions: Deficiency symptoms: (E) Magnesium: Functions: Deficiency symptoms: (F) Calcium : Functions: Deficiency symptoms : 5. Role Of Micronutrients And Their Deficiency Symptoms:<\/p>\n (A) Iron: Iron is absorbed mainly in the form of ferric ions (Fe3+<\/sup>).<\/p>\n Functions: Deficiency symptoms : (B) Copper: It is absorbed as cupric ions (Cu++<\/sup>). Deficiency symptoms : (C) Boron: It is absorbed as BO3<\/sub>3-<\/sup>\u00a0or B4<\/sub>O7<\/sub>2-<\/sup>. Deficiency symptoms: (D) Zinc : It is obtained by plants as Zn++<\/sup> ions. Deficiency symptoms: (E) Manganese : It is obtained by plants as Mn++<\/sup> ions. Deficiency symptoms: (F) Molybdenum : Plants obtain molybdenum as molybdate ions (MoO2<\/sub>2-<\/sup>).<\/p>\n Functions: (G) Chlorine : It is taken in the form of chloride ions. Deficiency symptoms : 6. Deficiency Symptoms:<\/p>\n \u2022 The common deficiency symptoms include : (ii) Necrosis : It refers to the death of tissues (especially of leaves) (iii) Inhibition of Cell Division : It is caused by deficiency of potassium, nitrogen, and molybdenum. \u2022 The deficiency symptoms tend to appear first in the young tissues in the case of elements that are relatively immobile, and are not transported out of the mature organs. e.g., Sulphur, and calcium, which form structural components.<\/p>\n The deficiency symptoms tend to appear first in older tissues, if the elements are actively mobile, they are withdrawn from the senescing organs, and transported to young tissues. e.g., Nitrogen, potassium and magnesium.<\/p>\n 7. Toxicity Of Micronutrients:<\/p>\n 8. Mechanism Of Absorption Of Elements:<\/p>\n 9. Translocation Of Solutes:<\/p>\n 10. Metabolism Of Nitrogen: Nitrogen cycle involves the following steps : (i) Nitrogen Fixation: –<\/p>\n (ii) Ammonification:<\/p>\n (iii) Nitrification: (iv) Denitrification :<\/p>\n B. Biological Nitrogen Fixation :<\/p>\n Free living nitrogen fixers include: Symbiotic nitrogen fixers include:<\/p>\n Biological nitrogen fixation requires the following three biochemical components. \u2022 The leghaemoglobin is a pink colour pigment similar to haemoglobin of vertebrates, and 11. Formation Of Root Nodules In Legumes:<\/p>\n Root Nodule Formation in a leguminous plant.<\/p>\n 12. Synthesis Of Amino Acids<\/p>\n \u2022 The ammonia formed by nitrogen fixation is used for the synthesis of amino acids (i) Reductive Amination : (ii) Transamination: 13. Amides:<\/p>\n Karnataka 1st PUC Biology Question Bank Chapter 11 Mineral Nutrition 1st PUC Biology Mineral Nutrition One Marks Questions and Answers Question 1. Name a plant which accumulates silica. Answer: Equisetum. Question 2. Mycorrhiza is a mutualistic association. How do the organisms involved in this association gain from each other? Answer: The fungus partner gets shelter …<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[81],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88208"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=88208"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88208\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=88208"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=88208"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=88208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n– It is the non cyclic path of electrons from PS II, and PS I to release ATP and NADPH2<\/sub>, with the help of protons and electrons from photolysis of water<\/p>\n<\/p>\n
\n<\/span>
\n– It is a light independent process occurring in stroma of chloroplast. It uses the assimilatory power (ATP and NADPH2<\/sub>) produced in a light reaction. It includes 4 main events namely:<\/p>\n<\/p>\n\n
\ne.g: Monocots like maize, sugarcane, ragi and dicots like euphorbia.<\/li>\n<\/ul>\n\n
\nIt is found that the rate of respiration is 3 to 5 times more in green photosynthetic plant cells in the presence of light. This phenomenon is called as photo respiration. It occurs only in C3<\/sub> plants. In C3<\/sub> plants, RUBP carboxylase is the main enzyme for glucose formation, but at high temperature, and high oxygen concentration functions as oxygenase and catalyses the oxidation of RUBP into one molecule of 3C compound phosphoglyceric acid, and one molecule of 2C compound, phosphoglycolic acid.<\/p>\n
\nAnswer:
\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-12-Mineral-Nutrition-7.png\")
<\/p>\n<\/p>\n
\nHow is sulphur important for plants? Name the amino acids in which it is present
\nAnswer:
\nSulphur is a component of two amino acids, vitamins, thiamine, biotin, Coenzyme A, lipoic acid, glutathione, and ferredoxin (FeS). Sulphur containing Amino Acids, are Cysteine and Methionine.<\/p>\n
\nMarne the most crucial enzyme found in root nodules for N2<\/sub> fixation? Does it require a special pink coloured pigment for its functioning? Elaborate.
\nAnswer:
\nCrucial Enzyme. Nitrogenase.<\/p>\n1st PUC Biology Mineral Nutrition Three Marks Questions and Answers<\/h3>\n
\nHow are the minerals absorbed by the plants?
\nAnswer:
\nThe process of absorption occurs in two distinct phases.<\/p>\n\n
\nWhat are the conditions necessary for fixation of atmospheric nitrogen by Rhizobium. What is their role in Nz-fixation?
\nAnswer:
\nBiological Nitrogen Fixation :<\/p>\n\n
\nAzotobacter, Rhodospirillum, Clostridium (anaerobes), and Cyanobacteria like Nostoc, and Anabaena.<\/p>\n<\/p>\n\n
\n(i) A reducing agent, to transfer the hydrogen atoms to dinitrogen.
\n(ii) ATP, to provide energy.
\n(iii) The enzyme system – nitrogenase, a Mo-Fe protein and leghaemoglobin.<\/p>\n
\nfunctions as an oxygen scavenger, and protects the nitrogenase from oxygen.
\nN2<\/sub>+ 8e–<\/sup> + 8H+<\/sup> + 16ATP 2NH3<\/sub> + 16 ADP + 16 Pi + H2
\n<\/sub><\/p>\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-12-Mineral-Nutrition.2.png\")
<\/p>\n1st PUC Biology Mineral Nutrition Five Marks Questions and Answers<\/h3>\n
\nExplain with examples: macronutrients, micronutrients, beneficial nutrients, toxic elements and essential elements.
\nAnswer:
\nMacronutrients : They are essential elements which occur in concentration of 1-10 mg\/g of dry matter, e.g., C, H, O, N, P, K.<\/p>\n<\/p>\n
\nEssential Elements : They are those elements which are involved in some vital structural, and functional role in plants so that their deficiency will cause disorders while their absence results in non-completion of life cycle, e.g., C, H, O, N, P K Ca, Mg, S, etc.<\/p>\n
\nName at least five different deficiency symptoms in plants. Describe them, and correlate them with the concerned mineral deficiency.
\nAnswer:
\nDeficiency Symptoms:<\/p>\n
\n(i) Chiorosis: It is the loss of chlorophyll leading to yellowing of leaves. Deficiency of elements nitrogen, potassium, magnesium, sulphur, iron, manganese, zinc, and molybdenum cause chlorosis.<\/p>\n<\/p>\n
\nWhat are the steps involved in the formation of a root nodule?
\nAnswer:<\/p>\n\n
![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-12-Mineral-Nutrition.3.png\")
<\/p>\n\n
1st PUC Biology Mineral Nutrition Text Book Questions and Answers<\/h3>\n
\n
<\/p>\n\n
\n
\nOnly a few elements have been found to be absolutely essential for plant growth and metabolism.
\n(A) They are classified into two broad categories:
\n(i) Macronutrients and
\n(ii) Micronutrients<\/p>\n\n
<\/p>\n
\nIt is absorbed as NO3<\/sub>+<\/sup>, NO2<\/sub>+<\/sup> and NH4<\/sub>+<\/sup> ions.<\/p>\n
\nIt is a major constituent of amino acids, proteins, nucleic acids,vitamins, etc.<\/p>\n\n
\nIt is obtained as sulphates (50\/- ions).<\/p>\n
\n(i) It is the constituent of amino acids, methionine and cystine.
\n(ii) It also forms part- of ferredoxin, and vitamins like thiamine, biotin, and coenzyme-A. Deficiency<\/p>\n
\n(i) Chlorosis of younger leaves.
\n(ii) Stunted growth of plants.
\n(iii) Accumulation of anthocyanin (purple colouration).<\/p>\n<\/p>\n
\nIt is absorbed by plants in the form of phosphate ions, either as H2<\/sub>PO4<\/sub>–<\/sup> or HPO4<\/sub>3-<\/sup> Functions:
\n(i) It is a constituent of nucleotides, and nucleic acids.
\n(ii) It is present in cell membranes as phospholipids.
\n(iii) It is involved in phosphorylation reactions, and energy metabolism a~ A TP.<\/p>\n
\n(i) Deficiency causes purple or red spots on leaves.
\n(ii) Leaves also become dark (dull) green.
\n(iii) There is a delay in seed germination.
\n(iv) Premature fall of leaves and flower buds also occurs.<\/p>\n
\nPotassium is taken in as potassium ions (K+<\/sup>). It is more abundant in meristematic tissues like buds, root-tips, and young leaves.<\/p>\n
\n(i) It determines the anion-cation benefice in cells.
\n(ii) It controls the opening and closing of stomata.
\n(iii) It maintains turgidity (osmotic balance) in cells.
\n(iv) It activates a number of enzymes.
\n(v) It is also involved in protein synthesis.<\/p>\n
\n(i) Interveinal chlorosis.
\n(ii) Scorched leaf tips.
\n(iii) Loss of apical dominance and a bushy appearance of plants.
\n(iv) Loss of cambial activity.
\n(v) Shorter intemodes .
\n(vi) Disintegration of plastids.
\n(vii) Increased rate of respiration.<\/p>\n
\nIt is absorbed as Mg++<\/sup> ions by the plants.<\/p>\n<\/p>\n
\n(i) It is a constituent of chlorophyll (forms the central atom of the porphyrin ring).
\n(ii) It maintains the ribosome structure for protein synthesis.
\n(iii) It activates the enzymes of phosphate metabolism in respiration and photosynthesis.
\n(iv) It is also involved in the synthesis of DNA, RNA, and activation of enzymes.<\/p>\n
\n(i) Interveinal chlorosis and necrosis, first occurs in of older leaves.
\n(ii) Premature leaf fall.<\/p>\n
\nCalcium is obtained as calcium ions (Cat) from the soil.<\/p>\n
\n(i) It is necessary for selective permeability of cell membranes.
\n(ii) It occurs as calcium pectate in the middle lamella of cell wall, hence is necessary for cell enlargement.
\n(iii) It is used in the formation of mitotic spindles during cell division, hence is required in the meristematic, and differentiating tissues (root apex, and shoot apex).
\n(iv) It activates certain enzymes in the metabolism.<\/p>\n
\n(i) Stunted growth.
\n(ii) Necrosis of meristematic regions.<\/p>\n
\n(i) It is an important constituent of cytochromes and ferredoxin, involved in the electron transport.
\n(ii) It activates catalase.
\n(iii) It is involved in the synthesis of chlorophyll.<\/p>\n<\/p>\n
\n(i) Chlorosis starts with the intravenous regions, and results in chlorosis of the complete leaf.<\/p>\n
\nFunctions:
\n(i) It is associated with certain enzymes involved in the redox reactions.
\n(ii) It is essential for the overall metabolism.<\/p>\n
\n(i) Necrosis starts from the tip of young leaves and extends downwards.
\n(ii) In fruit trees, it causes die back of shoot (death of shoot meristem).
\n(iii) Leaves fall off, and bark becomes rough, and splits exuding gummy substances.<\/p>\n
\nFunctions:
\n(i) It is required for carbohydrate translocation (as sugar borate).
\n(ii) It is necessary for uptake and utilisation of calcium ions.
\n(iii) It is needed for pollen germination.
\n(iv) It is involved in cell elongation and cell differentiation.<\/p>\n
\n(i) Death of root and shoot tips.
\n(ii) Abscission of flowers.
\n(iii) Loss of apical dominance.
\n(iv) Absence of root nodules in leguminous plants.
\n(v) Small sized fruits.
\n(vi) Stunted roots.<\/p>\n<\/p>\n
\nFunctions:
\n(i) It is necessary for the synthesis of auxins.
\n(ii) It activates many enzymes, especially carboxylases.<\/p>\n
\n(i) Malformed (little) leaves.
\n(ii) Interveinal chlorosis.
\n(iii) Stunted growth.<\/p>\n
\nFunctions:
\n(i) It is necessary for photolysis of water in photosynthesis.
\n(ii) It activates many enzymes involved in photosynthesis, nitrogen metabolism, and respiration.<\/p>\n
\n(i) Chlorosis.
\n(ii) Grey spots on leaves.<\/p>\n
\n(i) It is a co-factor for enzyme nitrate reductase.
\n(ii) It is also necessary for nitrogenase.
\nDeficiency symptoms:
\n(i) Interveinal chlorosis.
\n(ii) Whiplike disease in cauliflower.
\n(iii) Necrosis, first observed in older leaves.<\/p>\n
\nFunctions:
\n(i) Along with Na+<\/sup> and K+<\/sup> ions, it determines the anion-cation balance in cells, and
\ndetermines the solute concentration.
\n(ii) It is necessary for photolysis of water in photosynthesis.
\n(iii) It may be required for cell division in leaves, and roots.<\/p>\n
\n(i) Wilted leaves.
\n(ii) Stunted root growth.
\n(iii) Reduced fruit formation.<\/p>\n<\/p>\n\n
\n(i) Chlorosis : It is the loss of chlorophyll leading to yellowing of leaves.
\nDeficiency of elements nitrogen, potassium, magnesium, sulphur, iron, manganese, zinc, and molybdenum cause chlorosis.<\/p>\n
\ne.g., Deficiency of elements like calcium, magnesium, copper, potassium.<\/p>\n
\n(iv) Delay in flowering: Deficiency of elements like nitrogen, sulphur, and molybdenum causes delay in flowering.<\/p>\n<\/p>\n\n
\n
<\/p>\n\n
\nA. Nitrogen Cycle:
\n\u2022 Nitrogen is a limiting nutrient for both natural, and agricultural ecosystems.
\n\u2022 It exists as two nitrogen atoms held together by strong triple covalent bonds (N = N).<\/p>\n
\n(i) Nitrogen fixation
\n(ii) Ammonification
\n(iii) Nitrification and
\n(iv) Denitrification.<\/p>\n\n
![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-12-Mineral-Nutrition.1.png\")
<\/p>\n\n
<\/p>\n
\n-Nitrification is the process of converting ammonia first into nitrite, and then into nitrate.
\n2NH3<\/sub> + 3O2<\/sub> \u2192 2NO2<\/sub> + 2H+<\/sup> + 2H2<\/sub>O
\n2NO2<\/sub> + O2<\/sub> \u21922NO3<\/sub><\/p>\n\n
\n
\n
\nAzotobacter, Rhodospirillum, Clostridium (anaerobes), and Cyanobacteria like Nostoc, and Anabaena.<\/p>\n<\/p>\n\n
\n(i) A reducing agent, to transfer the hydrogen atoms to dinitrogen.
\n(ii) ATP, to provide energy.
\n(iii) The enzyme system – nitrogenase, a Mo-Fe protein and leghaemoglobin.<\/p>\n
\nfunctions as an oxygen scavenger, and protects the nitrogenase from oxygen.
\nN2<\/sub>+ 8e–<\/sup> + 8H+<\/sup> + 16ATP 2NH3<\/sub> + 16 ADP + 16 Pi + H2
\n
\n<\/sub><\/p>\n\n
<\/p>\n\n
<\/p>\n
\n\u2022 There are two processes by which amino acids are synthesised.<\/p>\n
\nIn this process ammonia reacts with alpha ketoglutaric acid and forms glutamic acids, a-ketoglutaric acid + NH3+<\/sup> + NAD(P)H \u2192 Glutamic acid + H2<\/sub>O + NAD (P).
\nThe reaction is catalysed by glutamate dehydrogenase.<\/p>\n
\nIn this process, the amino group is transferred from one amino acid to the keto group of a keto-acid.
\nGlutamic acid is the main amino acid which transfers its NH2<\/sub> group to form seventeen other amino acids.<\/p>\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-12-Mineral-Nutrition.4.png\")
<\/p>\n\n
1st PUC Biology Question Bank with Answers<\/a><\/h4>\n","protected":false},"excerpt":{"rendered":"