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100 questions in this collection · Page 2 of 10
Question 11 of 100
📘 CLASS XI
Mineral Nutrition
Consider the following statements regarding the role of iron in plants:
I. Plants obtain iron in the form of ferric ions (Fe3+). II. It is required in larger amounts in comparison to other micronutrients. III. It is an important constituent of electron transfer proteins like ferredoxin and cytochromes. IV. It forms the central metal atom of the chlorophyll ring structure.
Which of the statements given above are correct?
Statements I, II, and III are correct. Iron is absorbed mainly as Fe3+, is required in greater amounts than other micronutrients, and is an essential component of cytochromes and ferredoxin. Statement IV is incorrect because magnesium is the central atom of the chlorophyll molecule.
Question 12 of 100
📘 CLASS XI
Mineral Nutrition
Analyze the following statements regarding manganese:
I. It is absorbed in the form of manganous ions (Mn2+). II. It activates many enzymes involved in photosynthesis, respiration, and nitrogen metabolism. III. Its best-defined function is the photolysis of water to liberate oxygen during photosynthesis. IV. It acts as an essential activator of the nitrogenase enzyme.
Which of the statements given above are correct?
Statements I, II, and III are correct. Manganese is absorbed as Mn2+, activates many enzymes involved in photosynthesis, respiration, and nitrogen metabolism, and plays a key role in the oxygen-evolving complex responsible for photolysis of water. Statement IV is incorrect because molybdenum, not manganese, is required for nitrogenase activity.
Question 13 of 100
📘 CLASS XI
Mineral Nutrition
Which of the following statements about zinc and copper are correct?
I. Zinc (Zn2+) activates various enzymes, especially carboxylases. II. Zinc is essential for the synthesis of auxins. III. Copper is absorbed by plants as cuprous (Cu+) ions. IV. Copper is associated with redox enzymes and is reversibly oxidized from Cu+ to Cu2+.
Select the correct combination.
Statements I, II, and IV are correct. Zinc activates several enzymes, particularly carboxylases, and is essential for auxin synthesis. Copper participates in oxidation-reduction reactions by cycling between Cu+ and Cu2+. Statement III is incorrect because plants absorb copper mainly as cupric (Cu2+) ions.
Question 14 of 100
📘 CLASS XI
Mineral Nutrition
Consider the following statements regarding boron and molybdenum:
I. Boron is required for the uptake and utilization of Ca2+, membrane functioning, and pollen germination. II. Boron is involved in cell elongation, cell differentiation, and carbohydrate translocation. III. Molybdenum is absorbed as molybdate ions and is a component of nitrogenase and nitrate reductase. IV. Boron is essential for nitrogen metabolism, acting as a component of nitrogenase.
Which of the statements given above are correct?
Statements I, II, and III are correct. Boron is essential for calcium utilization, membrane function, pollen germination, cell elongation, differentiation, and carbohydrate transport. Molybdenum is a constituent of nitrogenase and nitrate reductase. Statement IV is incorrect because molybdenum, not boron, is the component of nitrogenase.
Question 15 of 100
📘 CLASS XI
Mineral Nutrition
Regarding the role of chlorine in plant biology, consider the following statements:
I. It is absorbed in the form of chloride anion (Cl-). II. Along with Na+ and K+, it helps in determining the solute concentration and the anion-cation balance in cells. III. It is essential for the water-splitting reaction in photosynthesis, leading to oxygen evolution. IV. Because of its role in anion-cation balance, it is classified as a macronutrient.
Which of the statements given above are correct?
Statements I, II, and III are correct. Chlorine is absorbed as Cl-, helps maintain osmotic and ionic balance, and is essential for the photolysis of water during photosynthesis. Statement IV is incorrect because chlorine is an essential micronutrient, not a macronutrient.
Question 16 of 100
📘 CLASS XI
Mineral Nutrition
The mobility of essential elements determines the onset of deficiency symptoms. Analyze the following statements:
I. Elements that are actively mobilized (like nitrogen, potassium, and magnesium) show deficiency symptoms first in younger tissues. II. Deficiency symptoms of nitrogen, potassium, and magnesium are visible first in senescent leaves. III. Elements like sulphur and calcium are relatively immobile and are not easily transported out of mature organs. IV. Deficiency symptoms of immobile elements tend to appear first in the young tissues.
Which of the statements given above are correct?
Statements II, III, and IV are correct. Mobile nutrients such as nitrogen, potassium, and magnesium are readily translocated to young tissues, so deficiency symptoms first appear in older leaves. Relatively immobile elements like sulphur and calcium remain in mature tissues, causing deficiency symptoms to appear first in young tissues. Therefore, Statement I is incorrect.
Question 17 of 100
📘 CLASS XI
Mineral Nutrition
Match the deficiency symptoms with the corresponding elements:
I.Chlorosis (loss of chlorophyll): Caused by deficiency of N, K, Mg, S, Fe, Mn, Zn, and Mo. II.Necrosis (death of tissue): Caused by deficiency of Ca, Mg, Cu, and K. III.Inhibition of cell division: Caused by lack or low levels of N, K, S, and Mo. IV.Delay in flowering: Caused by low concentration of N, S, and Mo.
Which of the statements given above are correct?
All four statements are correct. Chlorosis, necrosis, inhibition of cell division, and delayed flowering are characteristic deficiency symptoms associated with the listed essential mineral elements as described in NCERT.
Question 18 of 100
📘 CLASS XI
Mineral Nutrition
Analyze the following statements regarding the mechanism of absorption of elements by plants:
I. The process of absorption can be demarcated into two main phases: an initial rapid passive phase followed by a slow active phase. II. In the first phase, ions are taken up into the outer space or apoplast of the cells, which usually occurs through selective, pore-like ion channels. III. In the second phase, ions are taken slowly into the inner space or symplast of the cells through active processes requiring metabolic energy. IV. The inward movement of ions into the cells is termed efflux, whereas the outward movement is termed influx.
Which of the statements given above are correct?
Statements I, II, and III are correct. Ion uptake involves a rapid passive apoplastic phase through selective ion channels followed by a slower active symplastic phase requiring metabolic energy. Statement IV is incorrect because inward movement of ions is called influx, whereas outward movement is called efflux.
Question 19 of 100
📘 CLASS XI
Mineral Nutrition
Consider the following statements regarding the translocation of solutes and soil as a nutrient reservoir:
I. Mineral salts are translocated through the xylem along with the ascending stream of water, which is pulled up through the plant by transpirational pull. II. Chemical analysis of xylem sap shows the presence of mineral salts in it. III. Use of radioisotopes of mineral elements has substantiated the view that plant nutrients are transported exclusively through the phloem. IV. Soil not only supplies minerals but also harbors nitrogen-fixing bacteria, other microbes, holds water, and supplies air to the roots.
Which of the statements given above are correct?
Statements I, II, and IV are correct. Mineral salts move upward through the xylem along with water under transpirational pull, and xylem sap contains dissolved mineral salts. Soil also provides minerals, water, air, and beneficial microorganisms. Statement III is incorrect because radioisotope studies confirm that mineral nutrients are transported mainly through the xylem, not the phloem.
Question 20 of 100
📘 CLASS XI
Mineral Nutrition
Which of the following statements regarding nitrification are correct?
I. Decomposition of organic nitrogen of dead plants and animals into ammonia is called nitrification. II. Ammonia is first oxidized to nitrite by the bacteria Nitrosomonas and/or Nitrococcus. III. Nitrite is further oxidized to nitrate with the help of the bacterium Nitrobacter. IV. These nitrifying bacteria are chemoautotrophs.
Select the correct combination.
Statements II, III, and IV are correct. Nitrification is a two-step oxidation process in which ammonia is converted to nitrite by Nitrosomonas/Nitrococcus and nitrite is converted to nitrate by Nitrobacter. These bacteria are chemoautotrophs. Statement I is incorrect because conversion of organic nitrogen into ammonia is called ammonification.