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100 questions in this collection · Page 7 of 10
Question 61 of 100
📘 CLASS XI
Mineral Nutrition
Read the following statements about the role of boron in plants:
I. Boron is absorbed as BO33- or B4O72-. II. It is essential for the uptake and utilization of calcium (Ca2+). III. It is required for membrane functioning and pollen germination. IV. It plays a role in cell division, but is completely uninvolved in cell elongation and carbohydrate translocation.
Explanation: Statements I, II, and III are correct. Boron is absorbed as borate/tetraborate ions and is essential for calcium utilization, membrane function, and pollen germination. Statement IV is incorrect because boron also participates in cell elongation, cell differentiation, and carbohydrate translocation.
Question 62 of 100
📘 CLASS XI
Mineral Nutrition
Consider the following statements regarding molybdenum and chlorine:
I. Molybdenum is obtained by plants as molybdate ions (MoO22+). II. Molybdenum is a critical component of nitrogenase and nitrate reductase. III. Chlorine is absorbed in the form of chloride anion (Cl-). IV. Chlorine, alongside Na+ and K+, helps determine the solute concentration and the anion-cation balance in cells.
Explanation: All four statements are correct. Molybdenum functions as a component of nitrogenase and nitrate reductase, while chloride helps maintain osmotic balance, electrical neutrality, and participates in the water-splitting reaction of photosynthesis.
Question 63 of 100
📘 CLASS XI
Mineral Nutrition
Analyze the following statements about critical concentration and deficiency symptoms:
I. The concentration of an essential element below which plant growth is retarded is termed the critical concentration. II. An element is said to be deficient when present below its critical concentration. III. Deficiency symptoms appear in different tissues based on the mobility of the element. IV. Deficiency symptoms of mobile elements like nitrogen, potassium, and magnesium appear first in the young, developing leaves.
Explanation: Statements I, II, and III are correct. Deficiency symptoms depend on critical concentration and the mobility of elements. Statement IV is incorrect because mobile elements are retranslocated to young tissues, so deficiency symptoms first appear in older leaves.
Question 64 of 100
📘 CLASS XI
Mineral Nutrition
Consider the following statements regarding immobile elements:
I. Elements that are relatively immobile are not easily transported out of mature organs. II. Deficiency symptoms of immobile elements tend to appear first in the young tissues. III. Sulphur and calcium are examples of relatively immobile elements because they are structural components of the cell. IV. Immobile elements are actively broken down in older leaves and mobilized to the younger shoots during times of stress.
Explanation: Statements I, II, and III are correct. Immobile elements such as sulphur and calcium cannot be readily mobilized from mature tissues, so deficiency symptoms first appear in young tissues. Statement IV is incorrect because immobile elements are not easily remobilized.
Question 65 of 100
📘 CLASS XI
Mineral Nutrition
Analyze the diagnostic symptoms of element deficiencies:
I.Chlorosis is caused by the deficiency of N, K, Mg, S, Fe, Mn, Zn, and Mo. II.Necrosis is caused by the deficiency of Ca, Mg, Cu, and K. III.Inhibition of cell division is caused by the lack of N, K, S, and Mo. IV.Delay in flowering is caused by low concentrations of Ca, Mg, and Cu.
Explanation: Statements I, II, and III are correct. Chlorosis, necrosis, and inhibition of cell division are characteristic deficiency symptoms of the listed elements. Statement IV is incorrect because delayed flowering is caused by deficiencies of nitrogen, sulphur, and molybdenum.
Question 66 of 100
📘 CLASS XI
Mineral Nutrition
Regarding micronutrient toxicity, consider the following statements:
I. Any mineral ion concentration in tissues that reduces the dry weight of tissues by about 10 percent is considered toxic. II. Toxicity symptoms are exceptionally easy to identify because they remain identical across all plant species. III. Excess of one element can actively inhibit the uptake of another element.
Explanation: Statements I and III are correct. Toxicity is defined by approximately a 10% reduction in dry weight, and excess of one mineral can inhibit the uptake of another. Statement II is incorrect because toxicity symptoms vary among species and are often difficult to identify.
Question 67 of 100
📘 CLASS XI
Mineral Nutrition
Analyze the following statements regarding the dynamic biochemical interactions of manganese toxicity:
I. Manganese competes with iron and magnesium for uptake, and with magnesium for binding with enzymes. II. Manganese inhibits calcium translocation in the shoot apex. III. Excess manganese can induce deficiencies of iron, magnesium, and calcium. IV. The prominent symptom of manganese toxicity is the appearance of brown spots surrounded by chlorotic veins.
Explanation: All four statements are correct. Manganese toxicity interferes with iron, magnesium, and calcium metabolism, inhibits calcium translocation, and produces characteristic brown spots surrounded by chlorotic veins.
Question 68 of 100
📘 CLASS XI
Mineral Nutrition
Regarding the mechanism of mineral absorption, consider the following statements:
I. The initial rapid uptake of ions into the apoplast is passive. II. Passive entry of ions into the apoplast occurs through selective pore-forming transmembrane proteins called ion-channels. III. Entry or exit of ions to and from the symplast is active and requires the expenditure of metabolic energy. IV. Active transport occurs exclusively through open, non-selective physical spaces of the cell wall.
Explanation: Statements I, II, and III are correct. The apoplastic phase is passive and occurs through selective ion-channels, while the symplastic phase is active and requires metabolic energy. Statement IV is incorrect because active transport occurs across plasma membranes into the symplast, whereas the cell wall (apoplast) permits passive movement.
Question 69 of 100
📘 CLASS XI
Mineral Nutrition
Analyze the following statements regarding the translocation of solutes in plants:
I. Mineral salts are translocated through the phloem along with descending organic solutes. II. Translocation of mineral salts occurs through the xylem along with the ascending stream of water. III. Translocation is driven by the transpirational pull. IV. Chemical analysis of xylem sap and the use of radioisotopes confirm that minerals are transported via xylem.
Explanation: Statements II, III, and IV are correct. Mineral salts are transported through the xylem along with the ascending stream of water under transpirational pull. Chemical analysis of xylem sap and radioisotope studies confirm xylem transport. Statement I is incorrect because minerals are primarily translocated through the xylem, not the phloem.
Question 70 of 100
📘 CLASS XI
Mineral Nutrition
Read the statements regarding the soil as a nutrient reservoir:
I. Weathering and breakdown of rocks enrich the soil with dissolved ions and inorganic salts. II. Soil supplies minerals, harbors nitrogen-fixing microbes, holds water, and supplies air to roots. III. Since minerals are derived from soil, fertilizers must contain only micronutrients to maintain crop yields.
Explanation: Statements I and II are correct. Rock weathering enriches the soil with mineral ions, while soil supplies minerals, water, air, and beneficial microorganisms. Statement III is incorrect because fertilizers must supply both macronutrients and micronutrients depending on crop requirements.