\nThe nitrogenase enzyme and leghaemoglobin are two important compounds related to nitrogen fixation in plants. Mention the function of each. (MARCH-2010)<\/span>
\nAnswer:
\nNitrogenase – It is an enzyme involved in the conversion of N2<\/sub> to NH3<\/sub>
\nLeghaemoglobin – It is the pink coloured pigment act as an 02<\/sub> scavenger i.e it helps to prevent the combining of nitrogenase with 02<\/sub><\/p>\n
Question 2. Question 3. Question 4. Question 5. Question 6. Question 7. Question 8. Question 9. Question 10. Question 11. Question 12. Question 13. Question 14.
\nObserve the diagram and answer the following: (SAY-2010)<\/span>
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/05\/Plus-One-Botany-Chapter-Wise-Previous-Questions-Chapter-8-Mineral-Nutrition-1.png\")
\na) This is peculiar type of plant cultivation. Name it.
\nb) Aeration is necessary for the conduct of this type of cultivation. Why?
\nAnswer:
\na) Hydroponics
\nb) 02<\/sub> supply is needed for the optimum growth of plants\/absorption of nutrients<\/p>\n
\nMacronutrients and micronutrients are found to be absolutely essential for plant growth and metabolism.
\nName two macronutrients.\u00a0(MARCH-2011)<\/span>
\nAnswer:
\nCarbon, Hydrogen<\/p>\n
\nReduction of nitrogen to ammonia by living organisms is called bilogical nitrogen fixation. Can you write about one free living nitrogen fixing aerobic microbe?\u00a0(SAY-2011)<\/span>
\nAnswer:
\nAzotobactor<\/p>\n
\nIn the given flow chart of N2<\/sub> cycle write the name of organisms involved in the numbered places.\u00a0(SAY-2011)<\/span>
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/05\/Plus-One-Botany-Chapter-Wise-Previous-Questions-Chapter-8-Mineral-Nutrition-2.png\")
\nAnswer:
\nRhizobium
\nnitrococcus
\nnitrobactor
\nThiobacillus<\/p>\n
\na) Carotenoids are responsible for the pink colour of root nodule in pea plant.\u00a0(MARCH-2012)<\/span>
\nCorrect this false statement.
\nb) The pigment present in root nodule is called, \u2018Oxygen scavenger\u2019. Justify.
\nAnswer:
\na) Leg – haemoglobin
\nb) Leg – haemoglobin which protect nitrogenase enzyme and it act as oxygen scavenger.<\/p>\n
\nThe biochemical assay of some plants indicates the presence of Gold, Vanadium, Silicon etc. But, these elements are not considered as essential elements. Comment.\u00a0(SAY-2012)<\/span>
\nAnswer:
\n1) Essential elements required for normal growth and development.
\n2) Role of essential element is specific ie, not replaced by another element. Hence gold, Vanadium, Silicon etc. are not considered as essential elements.<\/p>\n
\n\u2018In a plant, deficiency of N2<\/sub> is visible in older parts and that of Ca is visible in younger parts\u2019. Critically evaluate the statement.\u00a0(SAY-2012)<\/span>
\nAnswer:
\nN2<\/sub> is a mobile element which move from older parts to younger parts
\nCa is an immobile element .which cannot move. Hence deficiency symptoms are found in younger parts<\/p>\n
\nNitrogen in the atmosphere exist as N2<\/sub> (N = N). But it cannot be absorbed by plants as such. So it converted into ammonia (NH3<\/sub>) by microorganisms and get fixed in the soil.\u00a0(SAY-2013)<\/span>
\na) Name the enzyme in the microorganisms which help to convert nitrogen into ammonia.
\nb) What is the role of leg-haemoglobin in this process?
\nAnswer:
\na) Nitrogenase
\nb) It act as 02<\/sub> scavenger that means it helps in preventing the combining of 02<\/sub> with nitrogenase<\/p>\n
\nThe deficiency symptoms of macro elements like calcium tend to appear first in the young tissues. Why?\u00a0(MARCH-2014)<\/span>
\nAnswer:
\nIt is an immobile element. So it cannot move to younger regions of plant.<\/p>\n
\nAmmonia is first oxidizied to nitrite and the nitrite is further oxidized to nitrate. Name the process. Give any one example of a bacterium which is involved in this process.\u00a0(MARCH-2014)<\/span>
\nAnswer:
\nNitrification, Ammonia is converted into nitrite with help of nitrosomonas but nitrite is converted into nitrate by nitrobactor.<\/p>\n
\nIf you cut through the root nodules of a pea plant, you will notice that the central portion is red or pink.\u00a0(MARCH-2014)<\/span>
\na) What makes the nodule pink?
\nb) Mention the role of this pink pigment.
\nAnswer:
\na) Leghaemoglobin
\nb)lt act as 02<\/sub> scavenger that means it helps in preventing the combining of 02<\/sub> with nitrogenase.<\/p>\n
\nObserve the diagram given below.\u00a0(SAY-2014)<\/span>
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/05\/Plus-One-Botany-Chapter-Wise-Previous-Questions-Chapter-8-Mineral-Nutrition-3.png\")
\na) Name this technique
\nb) Write two advantages of this technique
\nAnswer:
\na) Hydroponics
\nb) 1. It helps in studying deficiency symptoms
\n2. It is useful for the Commercial production of vegetables such as tomato.<\/p>\n
\nEven though more than sixty elements are found in different plants, all are not essential. Write any two criteria for the essentiality of an element.\u00a0(MARCH-2015)<\/span>
\nAnswer:
\n1) The element must be absolutely necessary for supporting normal growth and reproduction.
\n2) The requirement of the element must be specific and not replaceable by another element.<\/p>\n
![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/05\/Plus-One-Botany-Chapter-Wise-Previous-Questions-Chapter-8-Mineral-Nutrition-4.png\")