What are Hypertonic and Hypotonic Solutions?
In hypertonic solutions, the concentration of solutes outside the cell is higher than inside the cell. As a result, water moves out of the cell through Osmosis, causing the cell to shrink. In hypotonic solutions, the concentration of solutes outside the cell is lower than inside. Consequently, water flows into the cell, leading to swelling.
Key Points:
Hypertonic solution: Higher external solute concentration → water exits the cell → cell shrinks.
Hypotonic solution: Lower external solute concentration → water enters the cell → cell swells.
Comparison of Hypertonic vs Hypotonic
Isotonic Solutions
An isotonic solution has the same solute concentration as the cell. In this scenario, water moves in and out of the cell at an equal rate. Hence, there is no net change in the cell’s volume. Understanding isotonic, hypotonic and hypertonic solutions examples helps clarify the behaviour of cells in different environments:
Isotonic Example: A 0.9% saline solution is often isotonic to red blood cells.
Hypotonic Example: Distilled water is hypotonic to most cells.
Hypertonic Example: A highly concentrated salt solution is hypertonic compared to the cell interior.
Effects on Animal and Plant Cells
Animal Cells:
In a hypertonic environment, animal cells lose water, leading to shrinkage.
In a hypotonic environment, they gain water and may burst if the influx is excessive.
Plant Cells:
In a hypertonic environment, the Cell Membrane detaches from the cell wall (known as Plasmolysis).
In a hypotonic environment, water enters the plant cell, making it turgid. This is crucial for plants as it helps them maintain structure and rigidity.
Isotonic, Hypotonic and Hypertonic Solutions Examples in Daily Life
Sports Drinks: Often formulated to be isotonic with our body fluids, ensuring cells do not swell or shrink.
Gargling with Salt Water: This salt water is usually hypertonic, helping relieve a swollen throat by drawing out water from inflamed tissues.
Watering Plants: Pure water can be hypotonic for plant cells, enabling them to stand upright due to turgidity.
Additional Tips
Hypo means “low” → “Hippo” is big and swells → Hypotonic solutions cause cells to swell.
Hyper means “high” → Think of running around and losing water → Hypertonic solutions make cells shrink.
Iso means “equal” → No net movement → Isotonic solutions maintain the same cell size.
Quick Quiz (With Answers)
Question: Which type of solution causes a cell to lose water?
Answer: Hypertonic solution.
Question: Name the process where plant cells shrink away from the cell wall in a hypertonic solution.
Answer: Plasmolysis.
Question: In which solution does water move equally in and out of the cell?
Answer: Isotonic solution.
Question: Why do animal cells burst in a hypotonic solution, but plant cells do not?
Answer: Animal cells lack a rigid cell wall, whereas plant cells have a cell wall that provides structural support.
Question: What is the phenomenon called when red blood cells swell and burst in a hypotonic solution?
Answer: Haemolysis.
Related Topics
FAQs on Difference Between Hypertonic and Hypotonic Solutions
1. Why do some solutions not change cell size at all?
Because they are isotonic, meaning the solute concentration is the same inside and outside the cell.
2. Can a plant cell burst in a hypotonic solution like an animal cell?
Typically, no. The cell wall in plant cells prevents them from bursting under normal hypotonic conditions.
3. What happens if you drink a highly concentrated salt solution?
It can draw water out of your cells (hypertonic effect), causing dehydration.
4. Is the cytoplasm always hypotonic or hypertonic compared to the outside environment?
Not necessarily. The cytoplasm’s tonicity changes relative to the external environment, which depends on the solute levels inside and outside the cell.
5. Does turgor pressure occur in animal cells?
No. Turgor pressure is mainly observed in plant cells due to their rigid cell wall.
