Answer: Movement of minerals against concentration gradient using ATP and carrier proteins.
- A Movement of mineral ions from a region of high concentration to low concentration
- B Movement of minerals against concentration gradient using ATP and carrier proteins
- C Movement of minerals occurring mainly through the apoplast cell wall pathway
- D Largely unregulated random diffusion of mineral ions across the cell membrane
Correct answer: B. Movement of minerals against concentration gradient using ATP and carrier proteins
Explanation: Most mineral ions are absorbed by active transport - against their concentration gradient, requiring ATP and specific carrier proteins (permeases) in the plasma membrane. This allows plants to accumulate minerals at concentrations far higher than in soil.
Atmospheric N₂ is fixed into ammonia by nitrogen-fixing bacteria (protected from oxygen by leghaemoglobin in root nodules), converted to nitrate via nitrification for plant uptake, and eventually returned to the atmosphere as N₂ via denitrification, completing the cycle.
Concept context
Essential mineral elements, their roles and deficiency symptoms. Nitrogen fixation and soil nutrition.