Hypotonic Solution Definition, Examples

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The capacity to an extracellular fluid that allows water to flow into or out of cells via the process of osmosis is known as tonicity.. Tonicity is a measure of its the osmolarity. A closer look at the hypotonic solution can assist in understanding this more.

Additionally, it represents the sum of all solute present in the solution. Solutions that has lower osmolarity is limited in particle size per litre solution.

While a solution with greater osmolarity is comparatively richer in SOlute particles for each liter solution.

What is hypotonic solution?  – Hypotonic solution definition

A solution that has less dissolving particles (such as salts and other electrolytes) than normal blood and cells. Hypotonic solutions are often used to provide fluids via intravenous injections to patients who are hospitalized in the hope of preventing or treating dehydration.

Hypotonic solutions are solution with less solute content when compared with another solution. The solution can’t be considered hypotonic or isotonic, or hypertonic without having a solution for comparison.

Hypotonic describes the content of solute in one solution with respect to another solution. It is employed in biology to aid scientists define cells. Knowing the Osmolarity (concentration of the solution in terms of solutes per Liter) of various solutions could reveal to scientists the way in which gradients of solute and water will develop.

Due to the nature of diffusion, each solute in solution is likely to disperse from each the other until they are it is evenly dispersed. In the case of aqueous solutions, this happens primarily due to the interactions that water molecules of polarity are able to create with the solutes. The opposite sides of the molecule are charged with distinct charges that make temporary bonds, referred to as hydrogen bonds, with the other charged components of the solute molecules. Water molecules form clusters around solutes and move them away from the most concentrated concentrations of solutes and permit more water molecules to move into. So, if you decide to introduce a hypotonic mixture into a hypertonic one, the solution may initially contain zones of low and high concentration , but it will soon attain equilibrium. If the two substances are separated using a membrane that allows only water to pass through and out, the water will be able to move from the hypotonic solution to the hypertonic one, until both solutions are isotonic to each other.

Cells are essentially the result of an impermeable bag called that is, the plasma membrane. The plasma membrane has the ability to prevent solutes from spreading across the cell membrane while allowing water to move via osmosis into the cell’s cytoplasm. The membrane is encased with special proteins called membrane transport proteins, that assist in move specific substances across the membrane. Aquaporins are other proteins that maintain channels which only water can flow through. Cells must regulate their solute content to ensure that they don’t get too dry or overflowing with water. A cell that has an cytosol that has hypotonic to its environment is likely to be unable to replenish water in the hypertonic environment , which has more solutes. The water, which is driven to balance the two solutions is taken from the cell. Cells whose cytosol has very hypotonic in comparison to its surroundings will shred upand is believed as plasmolyzed. This is usually unfavorable for cells that require water to carry out many chemical reactions.

In the reverse situation the environment could be a hypotonic environment compared with the cells. In this situation water from the environment can be absorbed by the cell. If the hypotonic solutions of the environment is strong enough the cell might be lysed (split and open). Cells have numerous ways to control the movement of water. In fungi, plant and bacterial cells, the cell wall forms around the cell that prevents it from breaking. Cell walls are made of different polysaccharides, proteins, and various other molecules. When water enters the cell and presses through the walls of the cells pressure called turgor is generated. This pressure assists in pushing water back into the cell, thereby reducing the flow of water inwards. Below is a picture of the single plant cell in various conditions. The plant cell on the far right side is a turgid cell that is in a hypotonic medium.

It assists scientists in the description of cells. Osmolarity is the measurement of the concentration of a liquid within some quantity of solutes in a millilitre of various solutions could help scientists understand the manner the water gradient and solute gradients could develop.

What is the significance of it in Cells

Cells are always striving to maintain the balance between their external and internal environments.

If the interior of the cell has a lower level of solutes (hypotonic) which means that the extracellular environment contains a higher amount of solutes (hypertonic). Many of the essential components of cells including ions electrolytes and water typically diffuse along their levels, i.e. moving from high to low concentrations.

When the interior of the cell is hypotonic, the cell’s water flows away from cells and equalizes the concentration of solutes inside the cell and in its surroundings.

Living cells may retain the rigid structure because of this rule.

What Happens to Cells when it is placed in a hypotonic Solution?

If we place cells in hypotonic solution, it releases water through the cells.

As mentioned earlier in the previous paragraph, the hypotonic solution is composed of less solute as well as more water than the cell’s interior. Therefore, in accordance with rules of Osmosis water flows from its high level to its lesser through this semi-permeable membrane. In turn the cell’s cytoplasm is filled with water, and the cell grows. Because it is the case that the cell’s membrane is permeabilized for water molecules, it permits the passage of water through endosmosis. Hypotonic solutions are vital to cells in the event of cell dehydration since they allow the ingress of water into cells.

If the influx of water continues beyond the limit and the osmotic balance the cell could be disturbed. This means that cells will not be able to withstand the pressure the membrane of its cell will expand to the point where it will either lyze or explode.

What happens to RBCs when they are in the hypotonic solution? Hypotonic Solution

RBCs, which are the oxygen carriers of blood, can become over-inflated and then burst when exposed to hypotonic solutions. In any circumstance it can affect circulation of oxygen throughout the body.

Hypotonic Solution Example – Example of hypotonic solution

Plants and Fungi

Massive plants, fungi and even a few species manage the surrounding environment and help ensure that the surrounding environment remains a hypotonic environment in comparison against the cells. This results in cells that are and are turgid. The cells that are turgid push outwards on their wall cells, and press against each other, making a solid structure. They are continuously making use of solutes to keep the cell contents full of water. If you’ve ever used too much fertilizer in your garden, then you’ll know it’s not good for plants. The solutes added to the soil transform the hypotonic solution around root into an hypertonic one. The plants and roots will quickly be drained of all water. Organisms suffering from this type of condition rapidly die as they are unable to perform the necessary reactions for the life cycle.

Animal Cells

Animal cells don’t have an internal wall. Most animals depend on their skin to isolate the external environment from the internal organs. The fluid that is contained within the body cavity will be controlled by a set of proteins and membranes. This means that the fluid remains an isotonic or hypotonic solution in comparison to cells, which will keep them healthy and plump without damaging the cells. Maintaining concentration of solutes within an organism is referred to as osmoregulation. This is a common occurrence throughout all species. The majority of animals that reside in oceans have salt glands that expel the excess sodium from their bodies. Animals have to drink saltwater to absorb the salt water into their bodies. However, the salts need to be absorbed and eliminated from the body in order to keep the hypotonic balance.

More examples of Hypotonic Solution

  • Protists like paramecia, amoeba and amoeba don’t have a cell wall or cytoskeleton, they maintain their rigidity by controlling their tonicity. They are typically found in a hypotonic setting that causes a constant flow of water. To keep the cell’s structure and avoid them from bursting they have a special vacuole, also known as the contracted vacuole that helps remove excess water.
  • In marine creatures such as sea turtles and sharks the seawater already has a hypertonic effect to the cells’ sap. Thus, they keep an even higher level of hypertonicity within their cells, by eliminating the excess salt through its salt glands. In the process, their external environment becomes hypotonic, which allows them to live in seawater.
  • The freshwater species like trout and catfish are adapted to living in hypotonic conditions by constantly eliminating excess water from their bodies.
  • The Human body kidneys regulate the blood’s osmotic pressure by a thorough filtering and cleansing. It assists in regulating the level of water in the blood and also the mineral ions (salt) in blood.


A Plant Cell Is Placed In A Hypotonic Solution.What Will Happen?Will The Cell Burst?Why Or Why Not?

The cell will be swell but remain intact.
Plant cells are enclosed by rigid cell walls. When it is placed in a hypotonic solution (the solution which has a lower solute concentration than the cell), the process of osmosis takes place. Water moves from external environment to the cell and thus, the cells start to swell, however, rigid cell walls prevent it from bursting and therefore it remains intact and cells become turgid (that is swollen and hard).

How can a solution be hyperosmotic but hypotonic?

If the concentration of penetrating solutes is higher in the solution than in a cell
If the total concentration of solutes in the solution is less than in a cell
If the concentration of nonpenetrating solutes is less in the solution than in a cell
If the amount of solutes is the same in the cell and solution

A cell placed in a hypotonic solution will_____________

Ans: Swell
Hypotonic solution is a solution, which contains lesser solute concentration. In such a case, the water molecules move from outside to the inside of the cell through the cell membrane. This process is called as endosmosis by which cell gains water and swells up.

A 5% urea solution is hypotonic to a 10% urea solution. True or False


What happens when a cell is placed in a hypotonic solution?

Ans: water enters the cell toward the area of higher solute concentration.
Hypotonic solution is a solution having lower osmotic pressure i.e; having less solute and more water than other solutions. When a cell is placed in hypotonic solution water enters towards the higher concentration i.e., from cell to surrounding as the cell is hypertonic.
So, the correct option is ‘Water exits the cell toward the area of lower higher concentration’.

What prevents a plant cell from bursting in a hypotonic solution?

Plant cells have a cell wall around the outside than stops them from bursting, so a plant cell will swell up in a hypotonic solution, but will not burst.

What happens to a red blood cell in a hypotonic solution?

If placed in a hypotonic solution, a red blood cell will bloat up and may explode, while in a hypertonic solution, it will shrivel—making the cytoplasm dense and its contents concentrated—and may die.

How does the cell wall protect prokaryotic cells in a hypotonic solution?

How does the cell wall protect prokaryotic cells in a hypotonic solution? … Because cells shrivel in a hypotonic environment, the bacterial cell wall counteracts the outward osmotic pressure and prevents the cell from bursting.


  • https://www.medicinenet.com/hypotonic_solution/definition.htm
  • https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/mechanisms-of-transport-tonicity-and-osmoregulation/a/osmosis
  • https://www.sciencedirect.com/topics/immunology-and-microbiology/hypotonic-solution
  • https://www.shaalaa.com/question-bank-solutions/define-the-following-term-hypotonic-solution-colligative-properties-determination-molar-mass-osmosis-osmotic-pressure_91769
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  • https://www.biologyonline.com/dictionary/hypotonic-solution
  • https://biologydictionary.net/hypotonic-solution/
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