Q1. In cabbages, ‘Whiptail’ is a characteristic deficiency disease. It is caused by the deficiency of
- 1) Magnesium
- 2) Molybdenum
- 3) Boron
- 4) Chlorine
In cabbages, ‘Whiptail’ is caused by the deficiency of molybdenum which is characterised by the distortion of young leaves, a long mid-rib and poorly developed ragged blades.
Q2. What are the symptoms of chlorosis? Name any six elements whose deficiency causes necrosis.
Chlorosis occurs due to a lack of chlorophyll and the leaves turn yellow. Deficiency of nitrogen, potassium, iron, manganese, zinc and sulphur causes necrosis.
Q3. Which is essential for root hair growth?
- 1) S
- 2) Mo
- 3) Zn
- 4) Ca
Calcium is essential for the development of root hair as well as the root and stem apices.
Q4. Name the two amides found in plants.
Asparagine and glutamine
Q5. Manganese in toxic concentrations leads to the deficiency of
- 1) Phosphorus
- 2) Iron
- 3) Sulphur
- 4) Potassium
Manganese in toxic concentrations leads to the deficiency of calcium, iron and magnesium as it competes with iron and magnesium for nutrient uptake.
Q6. Name the elements responsible for the following functions: Maintenance of the ribosome structure Activation of catalase Germination of pollen grains Photolysis of water
Maintenance of the ribosome structure – Magnesium Activation of catalase – Iron Germination of pollen grains – Boron Photolysis of water – Chlorine
Q7. Which one of the following microbes forms a symbiotic association with plants and helps them in their nutrition.
- 1) Aspergillus
- 2) Glomus
- 3) Azotobacter
- 4) Trichoderma
Glomus is a fungus which forms a symbiotic association with the roots of plants (mycorrhiza) and helps them to absorb their nutrition.
Q8. Name the technique of growing plants in a nutrient solution.
Hydroponics is the technique of growing plants in a nutrient solution.
Q9. Name the deficiency symptom in which leaves turn yellow.
Q10. The function of leghaemoglobin (a red pigment) in root nodules of leguminous plant is
- 1) To regulate production of phenolic compounds
- 2) To regulate O2 supply in cells
- 3) To regulate the Mo supply in cells
- 4) To regulate CO2 supply in cells
Leghaemoglobin is a red pigment which gives a pinkish appearance to the nodules of leguminous plants. It combines with oxygen and regulates O2 supply in cells.
Q11. Name the enzyme for which Zn2+ acts as an activator.
Q12. What is nitrogen fixation? State the two natural sources to provide energy for nitrogen fixation.
The process of conversion of nitrogen to ammonia is called nitrogen fixation. Ultraviolet radiation and lightning provide energy for nitrogen fixation.
Q13. The middle lamella mainly contains
- 1) K
- 2) Ca
- 3) Na
- 4) Mg
Calcium is required for the synthesis of pectin in the middle lamella of the cell wall.
Q14. Which one of the following elements in plants is not remobilised?
- 1) Calcium
- 2) Phosphorus
- 3) Sulphur
- 4) Potassium
Calcium is an immobile element. It cannot be remobilised in plants, so its deficiency symptoms first appear in younger tissues rather than older ones. Phosphorus, potassium and sulphur are mobile elements. They can be remobilised in plants, so their deficiency symptoms first appear in older tissues.
Q15. The deficiency of which element affects the process of photosynthesis
- 1) Magnesium
- 2) Sulphur
- 3) Chlorine
- 4) Calcium
The deficiency of chlorine affects the process of photosynthesis as it plays an important role in PS II during photosynthesis.
Q16. What is the least concentration of minerals which can be detected in plants by using modern techniques?
The least concentration of minerals which can be detected in plants by using modern techniques is 10-8 g/ml.
Q17. Molybdenum is the essential constituent of
- 1) Nitrogenase
- 2) Growth regulators
- 3) Respiratory chain
- 4) Chlorophyll
Molybdenum is the essential constituent of nitrogenase enzyme. Nitrogenase is a Mo-Fe protein and catalyses the conversion of atmospheric nitrogen into ammonia.
Q18. Deficiency of which of the following can cause yellowing of intravenous regions of leaves?
- 1) Calcium
- 2) Copper
- 3) Potassium
- 4) Phosphorus
Interveinal chlorosis (i.e. yellowing of intravenous regions of leaves) occurs due to the deficiency of potassium.
Q19. Excess of manganese induces deficiency of other elements in plants. Justify.
Many times, excess of an element inhibits the uptake of another element by the plant. Manganese when becomes toxic (i.e. present more than its required concentration) causes brown spots to appear around the chlorotic veins. Manganese competes with iron for uptake. It competes with magnesium for binding with enzymes. It inhibits the calcium translocation in the shoot apex. Hence, excess of manganese induces deficiency of other elements in plants.
Q20. The function of leghaemoglobin in the root nodules of legumes is
- 1) Oxygen removal
- 2) Inhibition of nitrogenase activity
- 3) Expression of the nif gene
- 4) Nodule differentiation
Leghaemoglobin is a red-coloured pigment found in the root nodules of leguminous plants. It combines with oxygen and thus helps in oxygen removal from root nodules.
Q21. Name the element which activates the enzyme nitrogenase during nitrogen metabolism.
Q22. What is the name given to the movement of ions?
Q23. Which plant tissues die in necrosis?
Q24. Explain the method of hydroponics.
In hydroponics, a series of experiments are conducted in which roots of plants are immersed in a nutrient solution. Then an element is either added or removed or provided in varied concentration in the solution according to its suitability to the plant and its growth.
Plants are grown in tubes or troughs placed at a slight incline. A pump is provided which circulates the solution from a reservoir to the elevated end of the tube. The solution flows down the tubes and returns back to the reservoir. The roots of the plants get bathed continuously in an aerated solution.
Q25. State the reason due to which the minerals become available to the roots of plants.
Weathering and break down of rocks
Q26. Name the element essential for the synthesis of auxin.
Zinc ions are required for the synthesis of auxin.
Q27. Name the bacterium which can produce nodules on non-leguminous Alnus.
Q28. What is denitrification? Name the bacteria which perform denitrification.
Reduction of nitrate present in the soil into nitrogen is called denitrification. Bacteria Pseudomonas and Thiobacillus perform denitrification.
Q29. Name the element found in plants growing near nuclear testing sites.
Q30. Name any one bacterium which oxidises ammonia to nitrite.
Q31. Name the vegetables which are produced commercially by using hydroponics.
Seedless cucumber, tomato and lettuce
Q32. Name the element which plays an important role in biological nitrogen fixation.
- 1) Copper
- 2) Zinc
- 3) Molybdenum
- 4) Manganese
Molybdenum activates the enzymes involved in nitrogen metabolism and hence plays an important role in nitrogen fixation.
Q33. Name the following: Aerobic nitrogen-fixing bacteria Anaerobic nitrogen-fixing bacteria
Aerobic nitrogen-fixing bacteria – Azotobacter Anaerobic nitrogen-fixing bacteria – Rhodospirillum
Q34. Describe the importance of calcium in cell division.
Calcium pectate is necessary for the formation of the middle lamella, a part of the cell wall. Hence, calcium is important in the synthesis of the cell wall during cell division. It is required for the formation of the mitotic spindle.
Q35. Name parts of the plant where potassium is required in abundant quantities. State any two functions of potassium ions in plants.
Potassium ions are required in the meristematic tissues, buds, leaves and root tips. Potassium helps to maintain an anion-cation balance in cells. Potassium is required in all phosphorylation reactions.
Q36. When is an element considered toxic for plants?
Any mineral concentration which reduces the dry weight of plant tissues by 10% is toxic for plants.
Q37. Name the element required for the photolysis of water during photosynthesis.
Manganous ions or chlorine ions
Q38. Which element is responsible for the opening and closing of stomata to some extent?
Q39. Name the elements whose deficiencies are visible in senescent leaves.
Nitrogen, potassium and magnesium
Q40. Name the compound which when reacts with ammonia forms glutamic aid.
Q41. Define critical concentration.
The concentration of essential elements below which the growth of plants is retarded is called the critical concentration.
Q42. State the criteria which decide the essentiality of elements.
Criteria which decide the essentiality of elements: The element must be necessary for plant growth and reproduction. In the absence of such elements, plants do not complete their lifecycles. The deficiency of the element cannot be met by supplying some other element. The element must be directly involved in plant metabolism.
Q43. With the help of examples explain the role of essential elements in activating or inhibiting enzymes.
Magnesium is an activator for ribulose bisphosphate carboxylase-oxygenase as well as for phosphoenol pyruvate carboxylase. Both enzymes play an integral role in CO2 fixation in photosynthesis. Zinc ions activate alcohol dehydrogenase and the molybdenum of nitrogenase during nitrogen fixation.
Q44. State the role of Nitrobacter in nitrogen fixation.
Nitrobacter oxidises nitrite into nitrate.
Q45. Name the parts of the plants which require potassium ions more abundantly.
Meristematic tissues, buds, leaves and root tips require potassium abundantly.
Q46. Name the first phase of uptake of ions in the outer space of cells.
Q47. Name the two amino acids which contain sulphur.
The two amino acids which contain sulphur are cysteine and methionine.
Q48. What did Julius von Sachs demonstrate?
Julius von Sachs demonstrated that plants could be grown in a defined medium in the complete absence of soil and such plants also attain maturity.