Question

Land plants grow in soils which possess an osmotic concentration:
A). Hypotonic in reference to cells
B). Hypertonic in reference to cells
C).Isotonic in reference to cells
D). Ultratonic in reference to cells

Answer 1

Hint: Land plants require water for physiological processes. They gain it from the soil through endosmosis. Endosmosis can occur if only soil solution is hypotonic in reference to cells.

Complete Answer:
Hypotonic solution is the solution which possesses less concentration of solute. Solvent always flows out from high concentration of solvent to low concentration. If soil solution is hypotonic water will effuse from soil to roots.
The prefix to the word tonicity is ‘hyper’, which suggests “more” or “excess.Thus, an answer containing a better amount of the non-penetrating solutes as compared to the opposite solution across a membrane . Consider a cell placed within the hypertonic solution. During a hypertonic environment, the quantity of non-penetrating solutes within the solution outside the cytosol would be above the cytosolic concentration. As a result of this concentration difference, an osmotic gradient is generated across the membrane .
A common example of a hypotonic solution is 0.45% normal saline (half normal saline). When a patient develops diabetic ketoacidosis, the intracellular space becomes dehydrated, therefore the administration of a hypotonic solution helps to rehydrate the cells.

Hence the choice A is correct.

Note: during a hypotonic situation, the ECF has lower osmolarity than the fluid inside the cell, and water enters the cell.Changes in Cell Shape thanks to Dissolved Solutes: pressure changes the form of red blood cells in hypertonic, isotonic, and hypotonic solutions.