Q.26 Which one of the following statements is TRUE when a cell is kept in a hypotonic
solution?
(A) Water moves out of the cell
(B) Size of the cell remains same
(C) No movement of water takes place
(D) Size of the cell increases
In a hypotonic solution, water moves into the cell by osmosis due to higher solute concentration inside, causing the cell to swell and increase in size. This is a fundamental concept in cell biology for exams like GATE Life Sciences.
Correct Answer: (D) Size of the cell increases
Option Analysis
(A) Water moves out of the cell – False. This occurs in hypertonic solutions where external solute concentration is higher, causing plasmolysis or crenation.
(B) Size of the cell remains same – False. This happens in isotonic solutions with equal solute concentrations on both sides, resulting in no net water movement.
(C) No movement of water takes place – False. Osmosis always drives water movement across semipermeable membranes based on concentration gradients.
(D) Size of the cell increases – True. Hypotonic solutions have lower external solute concentration, so water enters the cell, leading to swelling (cytolysis in animal cells, turgor in plant cells).
Introduction to Cell Hypotonic Solution Behavior
When a cell is kept in hypotonic solution, water enters via osmosis, causing size of the cell increases. This key hypotonic solution effect tests tonicity understanding in biology exams like GATE Life Sciences.
Osmosis Mechanism in Hypotonic Solution
Hypotonic solutions have lower solute concentration outside the cell. Water moves into the cell down its gradient across the semipermeable membrane, equalizing concentrations. Result: Cell swells.
Effects on Animal vs Plant Cells
| Cell Type | Hypotonic Effect | Outcome |
|---|---|---|
| Animal | Water influx | Swells, may burst (hemolysis) |
| Plant | Water influx | Turgid (wall prevents bursting) |
Why Other Options Fail
-
Water moves out: Hypertonic scenario (crenation).
-
Size remains same: Isotonic balance.
-
No water movement: Ignores osmosis drive.
Exam Tips for Hypotonic Questions
Visualize: RBC in distilled water → bursts. Practice: Compare with hypertonic (shrinkage). Key for GATE XL, NEET.
Master cell hypotonic solution dynamics for perfect scores!
