Punjab State Board PSEB 11th Class Biology Important Questions Chapter 12 Mineral Nutrition Important Questions and Answers.
PSEB 11th Class Biology Important Questions Chapter 12 Mineral Nutrition
Very short answer type questions
Write the criteria for essentiality of an element.
Criteria for Essentiality of an Element
- The element must be absolutely necessary for supporting normal growth and reproduction; in the absence of the element, the plants do not complete their life cycle.
- The requirement of the element must be specific and not replaceable by another element, i.e., deficiency of any one element cannot be met by supplying some other element.
- The element must be directly involved in the metabolism of the plant.
Name two imrhobile elements in plants.
Calcium and sulphur are two immobile elements.
The deficiency of which element causes the death of stem and root apices?
The deficiency of this particular element causes the con dition of little leaf or mottle leaf in the plants. Name the element.
Deficiency of element zinc.
Deficiency of mineral nutrition is not responsible for etiolation. Yes or No. If no then explain why?
No, mineral deficiency is not responsible for etiolation because it is related to absence of light.
Where do the symptoms of deficiency of phosphorus appear first in the plant? And why?
The deficiency of phosphorus appears first in older leaves. Because it is a mobile element.
A particular macroelement is obtained by the plants from both mineral and non-mineral sources. Identify the element.
Nitrogen is the element which is obtained from both mineral and non-mineral sources.
Yellowish edges appear in leaves deficient in. [NCERT Exemplar]
Name the macronutrient which is a component of all organic compounds but is not obtained from soil. [NCERT Exemplar]
Ammonification of nitrogen during nitrogen cycle is bring about by a special process. Identify the process.
It is done by decomposition.
Organisms like Pseudomonas and Thiobacillus are of great significance in nitrogen cycle. How? [NCERT Exemplar]
These organisms carry out denitrification. They help to maintain the constant level of nitrogen in the atmosphere.
A farmer adds Azotobacter culture to soil before sowing maize. Which mineral element is being replenished? [NCERT Exemplar]
Short answer type questions
What are two macronutrients which are not obtained through soil as mineral nutrition? What is their importance?
Oxygen and carbon are not obtained through soil as mineral nutrition. Oxygen is necessary for respiration and carbon dioxide is necessary for photosynthesis.
A fanner 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.
Calcium deficiency can be due to shortage of water so proper irrigation should be done. Iron deficiency can be due to high alkalinity of soil. And excessive use of potassium can result in poor absorption of magnesium. The farmer should take corrective actions.
Which enzyme is found in root nodules of leguminous plants? What role does it play?
Nitrogenase is found in root nodules of leguminous plants. The enzyme binds with nitrogen and helps it in getting transported to the plant.
Write short notes on – Reductive animation and Transamination.
(i) Reductive Animation: In these processes, ammonia reacts with α-Ketoglutaric acid and forms glutamic acid as indicated in the equation given below :
(ii) Transamination: It involves the transfer of amino group from one amino acid to the keto group of a keto acid. Glutamic acid is the main amino acid from which the transfer of NH2, the amino group takes place and other amino acids are formed through transamination. The enzyme transaminase catalyses all such reactions. For example,
Long answer type questions
Hydroponics have been shown to be a successful technique for growing of plants, yet most of the crops are still grown on land. Why?
The technique of growing plants in a nutrient solution is known as hydroponics.
This method requires purified water and mineral nutrient salts. After a series of experiments, in which the roots of the plants were immersed in nutrient solutions and an element was added/removed or given in varied concentration, a mineral solution suitable for the plant growth was obtained.
By this method, essential elements were identified and their deficiency symptoms discovered. Hydroponics has been successfully employed as a technique for the commercial production of vegetables such as tomato, seedless cucumber and lettuce.
Yet, most of the crops are still grown on land because the nutrient solutions must be adequately aerated to obtain the optimum growth in hydroponis. Moreover, the minerals must be continuously added in the solution. No, such activity is required in the soil.
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.
(i) Can we artificially induce the property of nitrogen fixation in a plant, leguminous or non-leguminous?
(ii) What kind of relationship is observed between mycorrhiza and pine trees?
(iii) 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. [NCERT Exemplar]
(i) Yes, we can artificially induce the property of nitrogen fixation in a plant, leguminous or non-leguminous by genetic engineering. It involves the introduction of nif genes that cause the synthesis of nitrogenase enzyme by some vector in the plant in which we have to induce symbiosis.
(ii) Symbiotic association.
(iii) Yes, it is necessary for a-microbe to be in close association with a plant to provide mineral nutrition. For example, plants that contribute to nitrogen fixation include the legume family-Fabaceae or Leguminosae, such as clover, soyabeans, alfalfa, lupines and peanuts. They contain symbiotic bacteria called Rhizobia within nodules in their root systems, producing nitrogen compounds that help the plant to grow and compete with other plants.