HORTICULTURE

Detailed explanation-1: -All the minerals cannot be transported passively in the roots as the concentration is low in the soil and moreover they are present as a charged particle, which cannot cross the cell membrane. These are actively transported in the roots using energy stored as ATP.

Detailed explanation-2: -They cannot be absorbed by diffusion, because the minerals are in very low concentration. Instead, active transport is used. The root hair cells have carrier proteins in their cell membranes. These pick up the mineral ions and move them across the membrane into the cell against the concentration gradient .

Detailed explanation-3: -An example is the sodium-calcium exchanger or antiporter, which allows three sodium ions into the cell to transport one calcium out. This antiporter mechanism is important within the membranes of cardiac muscle cells in order to keep the calcium concentration in the cytoplasm low.

Detailed explanation-4: -Water and mineral salts first enter through the cell wall and cell membrane of the root hair cell by osmosis. Root hair cells are outgrowths at the tips of plants’ roots (Figure 5.27). They function solely to take up water and mineral salts.

Detailed explanation-5: -Mineral ions are absorbed by active transport. They are present in higher concentrations in the roots compared to the surrounding soil and are charged molecules. Calcium and magnesium are examples of ions required by plants for growth.