Please refer to Mineral Nutrition Class 11 Biology Exam Questions provided below. These questions and answers for Class 11 Biology have been designed based on the past trend of questions and important topics in your class 11 Biology books. You should go through all Class 11 Biology Important Questions provided by our teachers which will help you to get more marks in upcoming exams.
Class 11 Biology Exam Questions Mineral Nutrition
Class 11 Biology students should read and understand the important questions and answers provided below for Mineral Nutrition which will help them to understand all important and difficult topics.
Objective Type Questions
Question. Fe deficiency causes _____ leaves to turn ______
(a) Old yellow
(d) Old, brown spotted
Question. Which of the following compounds is used directly to build proteins?
Question. The cell of root nodule in leguminous plant shows a rod shaped structure called ______
(b) Infection thread
Question. The five elements that comprise most proteins are
Question. All N2 fixers belong to
(b) Eubacteria and Plantae
Question. Nitrogenase enzymes are extremely sensitive to _____ molecules
Question. Plants take up sulphur in the _____ form and phosphorus in the _____ form
(a) Reduced, Oxidised
(c) Reduced, Reduced
Question. Which of the following statements about the chemical process of N2, fixation in cells is true?
(a) It is enhanced by high O2 concentrations
(b) Very little energy in the form of ATP is needed
(c) All three bonds between nitrogen atoms are broken simultaneously
(d) Hydrogen atoms are added to nitrogen to form NH3 molecules
Question. The relationship between Rhizobium and the roots of legumes can be best described by which of the following terms?
Question. Nitrate reduction
(a) Is Performed by plants
(b) Take place in mitochondria
(c) Is catalysed by nitrogenase
(d) Performed by specialized plant cells located in the root
Question. Which one is the major constitiuent of proteins, nucleic acids, vitamins and hormones?
Question. Which of the following is false about amides?
(a) They are AA derivatives in which –OH of COOH is replaced by another NH2 group
(b) They are double aminated keto acids
(c) Amides are transported by phloem generally
(d) Amides link C and N metabolism
Question. Which of the following characteristics defines an element as essential element for a particular species?
(a) If it is missing a plant cannot grow or reproduce normally
(b) If it is absent other nutrients may be substituted for it
(c) If it is present in high concentration plant growth increases
(d) For high seed production it has to be added as fertilizers
Question. A mineral deficiency is likely to affect older leaves more than younger leaves if
(a) The mineral is micronutrient
(b) The older leaves are in direct sunlight
(c) The mineral is very mobile within plant
(d) The mineral is needed for chlorophyII synthesis
Question. The symptoms of toxicity are difficult to identify because of
(a) Presence of water in soil
(c) Primary symptoms
(d) Many a times excess of micronutrients interfere in the absorption and functioning of other nutrients
Question. The toxicity symptoms of Mn like brown spots surrounded by chlorotic veins is due to
(a) Deficiency of Mn only
(b) Excess of Fe
(c) Excess of Mg
(d) Combined deficiency symptoms of Fe,Mg and Ca
Question. Which one of the following statements can best explain the term critical concentration?
(a) Essential element concentration below which the plant growth is reduced
(b) Micronutrient concentration below which plant growth becomes stunted
(c) Essential element concentration below which plant remains in the vegetative phase
(d) Essential element concentration below which chlorosis occurs
Question. Plants cannot be grown in
(a) Soil with essential minerals
(b) Water with essential minerals
(c) Either soil or water with essential minerals
(d) Water or soil without essential minerals
Question. The deficiencies of micronutrients not only affects growth of plants but also vital function such as Photosynthetic mitochondrial electron flow. Among the list given below which group of three elements shall affect most both photosynthetic and mitochondrial electron tranport?
(a) Co, Ni, Mo
(b) Ca, K, Na
(c) Mn, Co, Ca
(d) Cu, Mn, Fe
Question. Ammonifying bacteria in the soil
(a) Convert ammonium to nitrate
(b) Fix nitrogen
(c) Convert nitrogen in organic molecules into ammonium
(d) Convert Nitrogen to Ammonia
Question. Deficiency of which mineral causes deficiency of N
Question. Minerals which maintain cation–anion balance in cells are
(a) CI and K
(b) K and Fe
(c) CI and Mg
(d) Ca and Mg
Question. Which of the following elements are required for chlorophyII synthesis?
(a) Fe and Mg
(b) Mo and Ca
(c) Cu and Ca
(d) Ca and K
Question. Which of the following is a component of vitamin (thiamine, biotin), Acetyl CoA, cysteine, methionine and ferredoxin?
Question. I. Help in the formation of middle lamella
II. Needed in spindle fibre formation
III. Accumulates in older leaves
IV. Involved in normal functioning of cell membrane
V. Activates certain enzymes like succinate dehydrogenase
The above list is associated with
Question. Match the column I with column II
|Column – I||Column – II|
|A. Mg||I. Found in some amino acids|
|B. S||II. Structural component of chlorophyll|
|C. I||III. Not important for plants|
|D. Mn||IV. Required for photolysis of water|
(a) A – II, B – I, C – III, D – IV
(b) A – I, B – II, C – III, D – IV
(c) A – I, B – III, C – I, D – IV
(d) A – II, B – III, C – I, D – IV
Question. Which element is very essential for uptake and utillization of Ca2+ membrane function, pollen germination and carbohydrate translocation via phloem?
Question. The first experiments on hydroponics were performed by
Question. Choose the correct statement(s)
A. Solution culture / Hydroponics contains all essential minerals except one, the usefulness of which is to be determined
B. Na, Si, Co and Selenium are beneficial element required by higher plants
C. Zn is the activator of nitrogenase while Mo is the activator of alcohol dehydrogenase
D. Zn is needed for auxin synthesis
Question. Which mineral is required in larger amount in comparison to other micronutrients?
Very Short Answer Type Questions:
Question. Nitrogen fixation is shown by prokaryotes and not eukaryotes. Comment.
Ans. Few prokaryotes like Rhizobium, Anabaena and Nostoc contains the enzyme nitrogenase, needed for the biological nitrogen-fixation. Eukaryotes do not possess this enzyme, therefore are unable to fix nitrogen.
Question. What is common to Nepenthes, Utricularia and Drosera with regard to mode of nutrition?
Ans. All the above mentioned plants are carnivorous (insectivorous) plants. These trap insects and digest them by proteolytic enzymes and thus, make up their nitrogen deficiency.
Question. Name a plant, which accumulate silicon.
Ans. Oryza sativa and Triticum aestivum are silicon accumulators. These plants actively absorb silicon and accumulate them in their biomass.
Question. A farmer adds Azotobacter culture to soil before sowing maize. Which mineral element is being replenished?
Ans. Azotobacter is a free living bacteria in the soil. It helps some cereal crops like maize (Zea mays) in nitrogen fixation. The farmer adds Azotobacter culture to the maize field for enhancing the nitrogen element in the soil by the process of biological nitrogen-fixation.
Question. Complete the equation for reductive amination ……… .
Ans. Reductive Amination Ammonia combines with a keto acid (like a-ketoglutaric acid or oxaloacetic acid) to form amino acid in presence of a reduced coenzyme (NADH, NADPH) and enzyme dehydrogenase (e.g., glutamate dehydrogenase, aspartate dehydrogenase).
Question. Think of a plant which lacks chlorophyll. From where will it obtain nutrition? Give an example of such a type of plant.
Ans. An angiospermic plant called Monotrapa do not contain chlorophyll. It grows on some other plant as a parasite and derive nutrition from the host plant. This plant is commonly known as ghost plant.
Question. Name the macronutrient which is a component of all organic compounds but it not obtained from soil.
Ans. Carbon is an essential element. Plant take it from atmosphere in the form of CO2. It’s concentration in atmosphere is about 0.03%. Plants use CO2 for photosynthesis (as a source of carbon) to synthesises glucose.
Question. Mycorrhiza is a mutualistic association. How do the organisms involved in this association gain from each other?
Ans. A mycorrhiza is a symbiotic association between a fungus and the roots of vascular plants (mainly gymnosperms). This mutualistic association provides fungus a constant and direct supply of carbohydrates (glucose and sucrose).
In return, plant gains the benefit of the mycelium of fungus which enhances its absorptive capacity for water and minerals due to the large surface area of mycelium.
Question. Plants with zinc deficiency show reduced biosynthesis of
Ans. Plant with zinc deficiency shows, reduced biosynthesis of auxin. Zinc is the microelement that is absorbed by almost all parts of the plant in the form of Zn2+ ion.
It functions as a constituent of carbonic anhydrase and auxin. It also activates various enzymes especially carboxylases and dehydrogenases.
Question. Carnivorous plants like Nepenthes and venus fly trap have nutritional adaptations. Which nutrient do they especially obtain and from where?
Ans. Nepenthes and venus fly trap grow in nitrogen deficient soil. So, they make up their nitrogen deficiency by trapping insects for which they have developed special adaptations.
Question. Name one non-symbiotic nitrogen fixing prokaryote.
Ans. Azotobacter is a non-symbotic nitrogen fixing prokaryote. It flourishs in the rice fields.
Question. Rice fields produce an important green house gas. Name it.
Ans. Rice fields remain logged with excess water which harbour the great microbial activity.
Many anaerobic bacteria also grow in these areas and release methane which is a green house gas.
Question. Name an insectivorous angiosperm.
Ans. (i) Dischidia (ii) Utricularia
Question. What type of conditions are created by leghaemoglobin in the root nodule of a legume?
Ans. Leghaemoglobin is responsible for creating anaerobic conditions in the root nodules of the legume plant. It acts as an oxygen scavenger, protecting enzyme nitrogenase to come in contact with oxygen and help in the proper functioning of enzyme, i.e., conversion of atmospheric nitrogen to ammonia (NH3).
Question. Yellowish edges appear in leaves deficient in.
Ans. Yellowish edges or chlorosis appears in the leaves, deficient in nitrogen. Nitrogen deficiency also causes delaying of flowering, interference in protein synthesis and dormacy of lateral buds.
Question. Excess of Mn in soil leads to deficiency of Ca, Mg and Fe. Justify.
Ans. Manganese (Mn2+) becomes toxic when absorbed by plants in higher amounts. The toxicity expressed in form of brown spots surrounded by chlorotic vein.
It is due to the following reasons
(i) Reduction in uptake of Fe3+ and Mn2+.
(ii) Inhibition of binding of Mn2+ to specific enzymes.
(iii) Inhibition of Ca2+ translocation in shoot apex.
Thus, excess ofMn2+ causes deficiency of iron, magnesium and calcium.
Short Answer Type Questions:
Question. Carefully observed the following figure
(a) Name the technique shown in the figure and the scientist who demonstrated this technique for the first time.
(b) Name atleast 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?
Ans. (a) Hydroponics, Julius Von Sachs (1860)
(b) (i) Solanum lycopersicum (tomato)
(ii) Hibiscus asculentus (ladiesfinger)
(iii) Solanum melongena (brinjal)
(c) Aerating tube Provides oxygen for the normal growth and development of the roots growing in the liquid solution. Feeding funnel is used to add water and nutrients in the hydroponic system when required.
Question. A farmer adds/supplies Na, Ca, Mg and Fe regularly to his field and yet he observes that the plants show deficiency of Ca, Mg and Fe. Give a valid reason and suggest a way to help the farmer improve the growth of plants.
Ans. Plant can tolerate a specific amount of micronutrients. A slight lesser amount of it can cause deficiency symptoms and a slight higher amount can cause toxicity. The mineral ion
concentration which reduces the dry weight of the tissues by 10% is called toxic concentration.
This concentration is different for different micronutrients as well as for different plants, e.g.,Mn2+ is toxic beyond 600 μgg−1 for soyabean and beyond 5300 μgg−1 for sunflower.
It has also been observed that the toxicity of one micronutrient causes the deficiency of other nutrients. To overcome such problems, farmers should use these nutrients in prescribed concentration so that the excess uptake of one element do not reduce the uptake of other element.
Question. Name the most crucial enzyme found in root nodules for N2-fixation? Does it require a special pink coloured pigment for its functioning? Elaborate.
Ans. Nitrogenase is the most crucial enzyme found in the root nodules for N2– fixation. It is a Mo − Fe protein that catalyses the conversion of atomospheric nitrogen to ammonia. Pink coloured pigment called leghaemoglobin creates anaerobic conditions for the functioning of nitrogenase enzyme.
Question. Carnivorous plants exhibit nutritional adaptation. Citing an example explain this fact.
Ans. Carnivorous (insectivorous) plants are mainly found in nitrogen deficient soil. To make up the nitrogen deficiency, they have developed insect trapping mechanism in which leaves have taken the shape of a pitcher containing insect digesting proteolytic enzymes. They trap insect and absorb the nitrogen derived from them.
Question. How is sulphur important for plants? Name the amino acids in which it is present.
Ans. Sulphur (S) is an important macronutrient in plants that is absorbed by the plants as SO42− ion. It mainly functions as a component of vitamins (biotin, thiamine), proteins,
coenzyme-A, amino acid (cystein and methionine) etc. It is also an essential component of ally sulphide (onion, garlic) and sinigrin (mustard).
Deficiency of sulphur can lead to chlorosis in young leaves, extensive root growth, formation of hard and woody stem. It also causes the reduction in juice content of citrus fruit and tea yellow disease of tea.
Sulphur is found in amino acids systeine, methionione, etc.
Question. How are organisms like Pseudomonas and Thiobacillus of great significance in nitrogen cycle?
Ans. In biological nitrogen fixation, the atmospheric N2 gets reduced to NH3 by nitrogenase reductase present in some prokaryotes. NH3 is then oxidises to NO2 and NO3 by some other bacteria (Nitrosomonas and Nitrobacter). Various steps involved in nitrogenfixation are as follows
Pseudomonas and Thiobacillus are involved in the process of denitrification. They convert nitrate(NO–3) and nitrite (NO–2) into free nitrogen (N2), which is released into the atmosphere.
Question. How are the terms ‘critical concentration’ and ‘deficient’ different from each other in terms of concentration of an essential element in plants?
Can you find the values of ‘critical concentration’ and ‘deficient’ for minerals—Fe and Zn?
Long Answer Type Questions:
Question. What are essential elements for plants? Give the criteria of essentiality?
How are minerals classifieds depending upon the amount in which they are needed by the plants?
Ans. An element is essential to plants if it is necessary for supporting its normal growth and reproduction. The requirement of this element must be specific and is not replaceable by any another element in the soil. They must be directly involved in the metabolism of the plant.
Criteria for Essentiality
An element can not be considered as essential merely on the basis of its presence in the plant. It is considered essential on the basis of the following criteria
(i) The plant is unable to grow normally and complete its life cycle in the absence of the element.
(ii) The element is specific and can not be replaced by another element.
(iii) The element plays a direct role in the metabolism of the plants.
The essential elements are further classified into two categories
(a) Macroelements These are the elements required by plants in larger quantities. These are C, H, O, N, P, K, Mg, Ca and S.
(b) Microelements (Trace elements) These are required by plants in low quantities (often less than 1 ppm). These include B, Zn, Mn, Cu, Mo, Cl, Fe and Ni.
Question. Hydroponics have been shown to be a successful technique for growing of plants. Yet most of the crops are still grown on land. Why?
Ans. Although, hydrophonics is a successful technique for plants still many crops are grown on land because
(i) The cost is the major concern. The setting and handling of hydrophonics requires much more investment than that of the soil based production.
(ii) Sanitization is extremely important especially with indoor hydroponic environments.
Water borne disease can spread quickly through some methods of hydroponic production.
(iii) Hydroponics is relatively a new technique and not used by the traditional farmers due to lack of knowledge.
(iv) Plants are less adaptable to the surrounding atmosphere. Hot weather and narrow oxygenation may minimise the production and quality of plant produce/yield.
Question. With the help of examples describe the classification of essential elements based on the function they perform.
Ans. Essential elements are involved in performing variety of functions in plants. Some of the major functions are enlisted below
(i) Frame work elements Essential elements as components of biomolecules and hence are structural elements of the cell. Carbon, hydrogen and oxygen are considered as framework elements because they constitute carbohydrates which form cell wall.
(ii) Protoplasmic elements N, P and S are considered as protoplasmic elements as they form protoplasm along with C, H and oxygen.
(iii) Catalytic enzyme Essential elements that activates or inhibit enzymes, i.e., without the presence of these elements some enzymes can not function e.g., Mg2+ acts as an activator for both ribulose biphosphate carboxylase oxygenase (Rubisco) and phosphoenol pyruvate carboxylase (PEP carboxylase).
Both are the critical enzymes involved in photosynthetic carbon fixation in plants.
(iv) Balancing elements Elements counteract the toxic effect of other minerals by causing ionic balance (e.g., calcium, magnesium and potassium).
(v) Influencing on the osmotic pressure of the cell Some essential elements alters the osmotic potential of the cell. Plant cells contain dissolved mineral elements in the cell sap influencing osmotic pressure of the cell, e.g., K is involved in opening and closing of stomata.
Question. 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.
Ans. (a) Artificial induction in leguminous and non-leguminous plants have been tried by scientists. It’s success rate is very low because gene expression is highly specific phenomenon.
Even if desired gene is introduced, it may not work because conditions for its expressions are very specific.
(b) Symbiotic mutualistic relationship (mutualism) is found between the pine roots and mycorrhiza as both are benefitted mutually.
(c) Yes, microbe has to be in close association, to develop a physical relationship for example Rhizobium gets into the root and involve root tissues, then only helps in nitrogen-fixation.
Question. Give the biochemical events occurring in the root nodule of a pulse plant.
What is the end product? What is its fate?
Ans. Formation of root nodule in pulse plant is the result of infection of roots by Rhizobium.
The following figure shows the process of nodule formation
In this process, transfer of NH2 group take place from one amino acid to other amino acid; enzyme transaminase catalyses this reaction.
Question. 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?
Ans. Plants can tolerate a specific amount of micronutrient. A slight lesser amount of it can cause deficiency symptom and a slight higher amount can cause toxicity. The mineral ion
concentration which reduces the dry weight of a tissue by 10% is called toxic concentration.
This concentration is different for different micronutrients as well as for different plant, e.g.,Mn2+ is toxic beyond 600 μgg−1 for soyabean and beyond 5300 μgg−1 for sunflower.
It is very difficult to identify the toxicity symptoms of mineral ion. It is because excess uptake of one element can reduces the uptake of other element at a time.
e.g., manganese (Mn2+) becomes toxic when absorbed by plants in higher amounts. The toxicity is expressed in form of brown spots surrounded by chlorotic vein.
It is due to the following
(i) Reduction in uptake of Fe3+ and Mg2+.
(ii) Inhibition of binding of Mg2+ to specific enzymes.
(iii) Inhibition of Ca2+ translocation in shoot apex.
Thus, excess of Mn2+ causes deficiency of iron, magnesium and calcium.
Question. 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 mobilised or relatively immobile?
(b) Name two elements which are highly mobile and two which are relatively immobile.
(c) How is the aspect of mobility of elements important to horticulture and agriculture?
Ans. (a) The plants try to supply more nutrients to its younger leaves than the older leaves. When nutrients are mobile, the deficiency symptoms are shown by the older leaves first because that particular nutrient reaches the top first and lower leaves does not get that nutrient.
(b) Highly mobile elements are P, K and Mn. Less mobile elements are Ca + and K+.
(c) The aspect of mobility of essential elements is important in horticulture and agriculture in the following ways
(i) A crop in which older leaves are harvested if show deficiency symptoms, will decrease its economic value.
(ii) The crops in which flowers, fruits and inflorescence are harvested, the immobile nutrients will not reach to the apex/tip because of immobility, so this will reduce the yield.
Question. Trace the events starting from the coming in contact of Rhizobium to a leguminous root till nodule formation. Add a note on importance of leg haemoglobin.
Ans. Formation of Root Nodule The coordinated activities of the legume and the Rhizobium bacteria depend on the chemical interaction between the symbiotic partners.
The principle stages in the nodule formation are summerised in the following diagram
Leg haemoglobin is an oxygen scavenger, it protects nitrogenase enzyme from O2 and also creates anaerobic conditions for the reduction of N2 to NH3 by Rhizobium.