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Active Diffusion vs. Passive Diffusion: What's the Difference?

Edited by Harlon Moss || By Janet White || Published on January 7, 2024
Active diffusion requires energy to move substances against a concentration gradient, while passive diffusion involves substances moving along a concentration gradient without energy input.

Key Differences

Active diffusion is a process requiring cellular energy (ATP) to transport molecules. Passive diffusion, however, does not require energy and relies on the natural movement of molecules.
In active diffusion, substances move against their concentration gradient. Conversely, in passive diffusion, substances move from an area of higher concentration to lower concentration.
Active diffusion often involves specific transport proteins. Passive diffusion, on the other hand, can occur through lipid bilayers or via channel proteins without energy.
Active diffusion is crucial for maintaining essential gradients in cells. Passive diffusion allows for the simple movement of molecules like oxygen and carbon dioxide.
Examples of active diffusion include sodium-potassium pump in cells. An example of passive diffusion is the exchange of gases in the lungs.

Comparison Chart

Energy Requirement

Requires energy (ATP)
Does not require energy

Concentration Gradient

Moves substances against concentration gradient
Moves along or down the concentration gradient

Transport Proteins

Often involves specific proteins
May occur through lipid bilayers or channel proteins

Cellular Function

Maintains vital gradients in cells
Facilitates basic molecule movement


Sodium-potassium pump, nutrient absorption
Oxygen exchange in lungs, osmosis

Active Diffusion and Passive Diffusion Definitions

Active Diffusion

It moves substances against their concentration gradient.
Active diffusion is used to pump sodium out of and potassium into the cell.

Passive Diffusion

Passive diffusion is the movement of substances without energy use.
Oxygen enters cells through passive diffusion.

Active Diffusion

Active diffusion is the energy-dependent transport of substances.
The cell uses active diffusion to absorb glucose from the bloodstream.

Passive Diffusion

Passive diffusion is important for osmosis.
Water moves into and out of cells by passive diffusion.

Active Diffusion

Active diffusion involves specific transport proteins.
Ion channels in neurons work through active diffusion.

Passive Diffusion

Passive diffusion can happen through lipid bilayers.
Fat-soluble vitamins are absorbed by passive diffusion through cell membranes.

Active Diffusion

It's essential for maintaining ion balances in cells.
Active diffusion helps in regulating calcium levels in muscle cells.

Passive Diffusion

It's a fundamental process for gas exchange in organisms.
The diffusion of gases in the lungs occurs passively.

Active Diffusion

Active diffusion can transport large or charged molecules.
Amino acids are often transported into cells via active diffusion.

Passive Diffusion

It occurs along a concentration gradient.
Carbon dioxide is released from cells into the bloodstream via passive diffusion.


How do substances move in active diffusion?

They move against their concentration gradient in active diffusion.

What role do proteins play in active diffusion?

Specific transport proteins facilitate active diffusion.

What drives active diffusion?

Cellular energy, typically ATP, drives active diffusion.

Does passive diffusion require cellular energy?

No, passive diffusion does not require energy.

Can active diffusion transport large molecules?

Yes, it can transport large and even charged molecules.

What is the direction of movement in passive diffusion?

It's from higher to lower concentration.

Can passive diffusion occur through membranes?

Yes, especially for small or nonpolar molecules.

What is an example of a molecule transported by active diffusion?

Glucose is often transported into cells by active diffusion.

Do plants use active diffusion?

Yes, for nutrient uptake and ion transport.

Is active diffusion selective?

Yes, it's highly selective based on the molecule and transport protein.

How does passive diffusion assist in breathing?

It allows oxygen to enter and carbon dioxide to leave the blood in the lungs.

Is active diffusion important for nerve function?

Yes, it's crucial for transmitting nerve signals.

Is osmosis a type of passive diffusion?

Yes, osmosis is passive diffusion specific to water.

Can active diffusion occur in all cells?

Most cells have some form of active diffusion mechanism.

Does water use passive diffusion?

Yes, water typically diffuses passively through cell membranes.

Is active diffusion faster than passive diffusion?

It can be, especially for large or polar molecules.

How does passive diffusion maintain equilibrium?

It helps balance concentrations across membranes, reaching equilibrium.

Can passive diffusion occur without a membrane?

Yes, it can occur in any gradient without a membrane.

How does temperature affect passive diffusion?

Higher temperatures generally increase the rate of passive diffusion.

What factors influence passive diffusion?

Concentration gradient, membrane permeability, and molecule size.
About Author
Written 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.
Edited 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.

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