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Endosmosis vs. Exosmosis: What's the Difference?

Edited by Janet White || By Harlon Moss || Updated on October 27, 2023
Endosmosis is the movement of water into a cell or compartment, while exosmosis is the movement of water out of a cell or compartment.

Key Differences

Endosmosis and exosmosis are two processes involving the movement of water across a semipermeable membrane. Endosmosis refers to the movement of water into a cell or compartment, typically when the external environment is less concentrated than the internal environment. Conversely, exosmosis denotes the movement of water out of a cell or compartment, occurring when the external environment is more concentrated than the internal environment.
The direction of water movement in endosmosis and exosmosis is determined by osmotic pressure. In endosmosis, water moves inward to balance the higher solute concentration inside the cell, thus reducing osmotic pressure. In exosmosis, water moves outward, drawn by the higher solute concentration outside the cell, in an attempt to equalize osmotic pressure across the membrane.
Both endosmosis and exosmosis play crucial roles in maintaining cellular balance. Endosmosis allows cells to absorb water, vital for cellular processes and maintaining turgidity. Exosmosis, on the other hand, enables cells to expel excess water, preventing cellular swelling and potential damage.
While endosmosis and exosmosis both involve water movement, their consequences for a cell are quite different. Endosmosis can lead to cell expansion and turgidity, essential for plant cell rigidity. Exosmosis can cause cell shrinkage or plasmolysis, particularly in plant cells, if excessive water loss occurs.

Comparison Chart

Direction of Water Movement

Into a cell or compartment
Out of a cell or compartment

Osmotic Pressure Influence

Moves water inward to reduce higher internal osmotic pressure
Moves water outward due to higher external osmotic pressure

Cellular Effect

Leads to absorption of water, increasing turgidity
Leads to expulsion of water, can cause shrinkage or plasmolysis

Environmental Condition

Occurs in hypotonic environments
Occurs in hypertonic environments

Role in Organisms

Important for cellular hydration and process
Crucial for preventing cellular overhydration and damage

Endosmosis and Exosmosis Definitions


Endosmosis is the inward movement of water across a membrane.
Endosmosis caused the cell to swell in the hypotonic solution.


Exosmosis is the outward movement of water across a membrane.
Exosmosis led to the dehydration of the cell in the saline solution.


Endosmosis increases cellular turgidity.
Endosmosis contributed to the plant cell's rigidity.


Exosmosis balances external osmotic pressure.
Exosmosis helped the cell adjust to the external osmotic pressure.


Endosmosis involves water absorption by cells.
Through endosmosis, the cell absorbed water and expanded.


Exosmosis occurs in hypertonic environments.
In saltwater, exosmosis challenged the survival of freshwater organisms.


Endosmosis balances internal osmotic pressure.
Endosmosis was vital in equalizing the cell’s osmotic pressure.


Exosmosis can cause cell shrinkage or plasmolysis.
Excessive exosmosis resulted in the plant cell’s plasmolysis.


Endosmosis occurs in hypotonic environments.
In freshwater, endosmosis helps amoeba regulate its internal water balance.


Exosmosis involves water expulsion from cells.
To combat overhydration, the cell underwent exosmosis.


The inward flow of a fluid through a permeable membrane toward a fluid of greater concentration.


The passage of a fluid through a semipermeable membrane toward a solution of lower concentration, especially the passage of water through a cell membrane into the surrounding medium.


Osmosis in which fluid flows through a membrane towards a region of higher concentration


Osmosis in which fluid flows through a membrane towards a region of lower concentration


See Exosmose.


How do endosmosis and exosmosis differ in water movement?

Endosmosis moves water into a cell, while exosmosis moves water out of a cell.

What is exosmosis?

Exosmosis is the movement of water out of a cell or compartment across a membrane.

In what type of solution does exosmosis occur?

Exosmosis commonly occurs in hypertonic solutions.

What is endosmosis?

Endosmosis is the movement of water into a cell or compartment across a membrane.

Can exosmosis lead to dehydration?

Excessive exosmosis can lead to cellular dehydration and related issues.

In what type of solution does endosmosis occur?

Endosmosis typically occurs in hypotonic solutions.

Is endosmosis vital for plant cells?

Yes, endosmosis is important for maintaining plant cell turgidity and structure.

Are endosmosis and exosmosis passive processes?

Yes, both are passive processes driven by concentration gradients.

Does exosmosis always harm cells?

Not always; exosmosis can be essential for preventing cellular overhydration.

Do animal cells undergo endosmosis and exosmosis?

Yes, animal cells also experience endosmosis and exosmosis.

What regulates endosmosis and exosmosis?

Osmotic pressure and concentration gradients regulate these processes.

How does endosmosis affect osmotic pressure?

Endosmosis reduces higher internal osmotic pressure by moving water inward.

Can exosmosis be reversed?

Exosmosis can be reversed if the external environment becomes hypotonic.

Is endosmosis important for kidney function?

Yes, endosmosis plays a role in water reabsorption in the kidneys.

Can endosmosis cause a cell to burst?

In extreme cases, excessive endosmosis can cause a cell to burst due to overhydration.

What is the result of exosmosis in plant cells?

Exosmosis in plant cells can lead to cell shrinkage or plasmolysis.

Can human cells undergo plasmolysis?

Human cells typically do not undergo plasmolysis due to the presence of cell membranes rather than cell walls.

What role does endosmosis play in human health?

Endosmosis is vital for cell hydration and nutrient absorption in the human body.

Do cells control endosmosis and exosmosis?

Cells can regulate these processes through membrane channels and osmoregulation.

How does exosmosis affect osmotic pressure?

Exosmosis equalizes higher external osmotic pressure by moving water outward.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.

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