Difference Between Osmosis and Diffusion

Difference Between Osmosis And Diffusion

Difference Between Osmosis and Diffusion


Osmosis is a sort of diffusion in which a material passes across a semipermeable membrane to bring the concentrations of two or more substances into equilibrium. In addition, it occurs in biology when a solvent, such as water, flows into or out of a cell according to the concentration of a solute, such as salt. Furthermore, osmosis occurs without the expenditure of any cell energy. Osmosis, for example, is responsible for the absorption of water from the soil. Because the concentration of plant roots is higher than that of soil, water flows into the roots.

The direction in which osmosis occurs is influenced by a number of variables. Concentration is the fundamental osmosis restriction. The ratio of solute material in a solution to the solvent in which it is dissolved is known as concentration.

In order to attain equilibrium, or a condition where the concentrations are balanced throughout, water will naturally migrate from a region with a lower concentration of solutes to an area with a greater concentration. Water will pass through whatever membrane it can if it is travelling to a higher-concentration location. Hypertonic regions have higher concentrations, whereas hypotonic areas have lower concentrations.

Factors affecting osmosis

  • When a high solute concentration area on one side of a membrane meets a low solute concentration area on the other, osmosis occurs. The faster osmosis happens, the greater the temperature. Because energy is expended to penetrate the membrane, this is due to the quantity of energy present in the water.
  • The rate of osmosis is directly affected by pressure. The faster osmosis occurs on one side of the membrane, the faster it occurs on the other. The concentration gradient is the same: the lower the concentration of a solute in water, the faster it travels across a membrane.
  • Osmosis occurs at a quicker rate when there is a bigger concentration difference
  • The rate of osmosis is directly affected by surface area. The bigger the surface area of the membrane, the easier it is for molecules to pass through. The smaller the surface area, on the other hand, the more difficult it is for molecules to get through the barrier. The difference in water potential, or discrepancy in water concentration, has a big role in osmosis speed. The bigger the gap, the more quickly osmosis occurs.

Importance of Osmosis

Importance Of Osmosis

Because it keeps the inside and exterior of a censer in balance, osmosis is essential to life. By regulating the quantities of water and intracellular fluids, osmosis assists in maintaining the organism’s internal environment. Osmosis also allows nutrients and minerals to enter the cell, which is important for cell viability.

Let’s take a look at some of the importances of osmosis:

  • The delivery of nutrients and the discharge of metabolic waste products are both influenced by osmosis.
  • It is in charge of absorbing water from the earth and transporting it to the plant’s higher portions via the xylem.
  • This mechanism regulates water transport from cell to cell.
  • Osmosis causes cell turgor, which controls plant and plant component movement.
  • Fruit and sporangia dehiscence is also controlled by osmosis.
  • Plants are protected against drought harm by higher osmotic pressure.
  • It keeps the equilibrium between water and intercellular fluid levels in a live organism’s internal environment stable.
  • It keeps the turgidity of cells in check.
  • It’s a method for plants to retain their water content despite regular water loss from transpiration.


Have you ever observed how helium balloons lose buoyancy over time? This is due to helium diffusing from a helium-rich environment within the balloon to a helium-poor one outside.

Diffusion is the propensity of molecules, atoms, ions, and other constituents of gases, liquids, and solids to become uniformly dispersed over the available area as a result of their random kinetic motion. The presence of kinetic energy in particles causes random kinetic motion.

In a liquid, gases and molecules tend to diffuse from a more concentrated environment to a less concentrated one. The diffusion of chemicals through a membrane is known as passive transport. This is a natural process in which no cellular energy is used.

Molecules will migrate from a highly concentrated state to a less concentrated state. Membrane permeability influences the rate of diffusion of various substances. Water, for example, may readily pass through cell membranes, while other molecules cannot. Through a process known as facilitated diffusion, they must be assisted through the cell membrane.

Factors affecting diffusion

  • Graham’s Law states that the rate of diffu­sion of a material is inversely related to the square root of its relative density.
  • The number of particles per unit volume, the density of the medium, the distance that diffusion must traverse, as well as temperature and pressure, all have an impact on diffusion.
  • The rate of diffusion slows as the density of the medium increases.
  • The rate of diffusion speeds up as the temperature rises. Sugar crystals don’t dissolve as quickly in ice cold water as they do in warm water because of this.
  • The difference in diffusion pressure at the two extremities of a system determines the rate of diffusion, which is inversely proportional to the distance between them.
  • When the concentration difference is greater, diffusion will be faster. Gases diffuse at a faster rate than liquids. The diffusion of solids is the slowest. A condition of equilibrium is obtained when the particles of the diffusing material are uniformly dispersed. It puts an end to any further movement.
  • If the two substances do not react, the diffusion of one substance’s particles is independent of the diffusion of another substance’s particles. It’s referred to as independent dissemination. The partial pressure is the diffusion pressure of the specific substance.

Importance of Diffusion

Importance Of Diffusion

  • Diffusion at the general body surface facilitates gas exchange in submerged hydrophytes.
  • Diffusion is a phenomenon that occurs when water vapours are exhaled.
  • The usage of a protein to promote the flow of molecules across a membrane is known as facilitated diffusion. Molecules flow via channels within the protein in some circumstances. In certain circumstances, the protein alters its form to allow molecules to flow through.
  • Because without diffusion, the cells and bodily tissues would be unable to obtain the nutrients required to keep the human body alive. The respiratory system is an example of diffusion in the body.
  • When you breathe in, oxygen diffuses from your lungs into your circulation, while carbon dioxide diffuses into your alveoli and is eventually expelled from your body.
  • Through the filtering mechanism known as nephrons, the kidney diffuses water out of the urine.
  • Another area where diffusion happens is the digestive system. The nutrients received by the cells are transferred and conveyed via the vessels on the other side of the membrane when we take food.

Read Also: What Is A Reverse Osmosis System?

Difference between osmosis and diffusion

Let’s have a look on difference between osmosis and diffusion

Diffusion Osmosis
Any material goes from a high-energy or high-concentration location to a low-energy or low-concentration area. Only water or another solvent may travel from a high-energy to a low-energy or low-concentration location.
Diffusion may happen in any liquid, solid, or gaseous media. Only a liquid medium allows osmosis to happen.
A semipermeable membrane is not required for diffusion. A semipermeable membrane is required for osmosis.
There is no concentration equalization in order to fill the area available. The concentration on both sides of the membrane is not the same.
Diffusion is unaffected by the potential of the solute, the pressure potential, or the potential of the water. In osmosis, solute potential plays a role.
Diffusion is not generally affected by hydrostatic pressure or turgor pressure. Osmosis is inhibited by hydrostatic and turgor pressures.
The presence of other particles is the most important factor in diffusion. The quantity of solute particles dissolved in the solvent is the most important factor in osmosis.
The goal of diffusion is to bring the system’s concentration (energy) into balance The movement in osmosis attempts, but fails, to equalize the concentration of the solvent.
It aids in mineral and vitamin absorption. Mineral and nutrient absorption are unrelated.
This is a procedure that cannot be halted or reversed. By adding more pressure to the solution side, the entire process may be stopped or reversed.
Particles flow in all directions at the same time. There is only one way for particles to flow.
This occurs between solutions that are similar and those that are distinct. Only occurs between solutions of comparable kinds.

Bottom line

Both osmosis and diffusion act to balance a solution’s concentration. Diffusion occurs when particles travel from a high-concentration area to a low-concentration area until equilibrium is attained. A semipermeable membrane is present in osmosis, allowing only the solvent molecules to travel freely to equalize concentration. Diffusion and osmosis are both passive transport processes, meaning they don’t need any extra energy to work. Particles travel from a high-concentration location to a low-concentration area in both diffusion and osmosis.

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