Osmosis is a natural process that balances the amount of water and other cellular fluid in living cells. It also carries important molecules and particles to and from the cell. It happens by the passive movement of a solvent across a semipermeable membrane from a region with a lower solute concentration to a region with a higher one, up a concentration gradient. This movement is driven by the osmotic pressure of the solvent.

What is Tonicity

The rate at which osmosis occurs depends on the tonicity of the solution. Tonicity is a measurement of the relative concentration of solute and solvent in a solution expressed as osmoles per litre (Osm/L). When a solution has a higher tonicity than the cell, it exerts more osmotic pressure against the cell. This causes the solvent to move faster in order to equalize the concentrations on both sides of the membrane. In addition, the direction of osmosis changes when there is pressure applied in excess to that which is exerted by the solvent molecules.

Osmosis can occur from either direction, depending on the cell’s environment. If it is placed in a hypertonic solution, it will experience endosmosis. This causes the cell to swell up and takes in water, important molecules and particles for growth. When the cell is placed in a hypotonic solution, it experiences exosmosis. This results in the loss of water from the cell and it shrinks. Blackbook Of General Awareness Latest Edition Pdf

Reverse Osmosis

There is another type of osmosis, known as reverse osmosis. This occurs when a draw solution, with a higher solute concentration is used to force solvent molecules through a semipermeable membrane into the sample solution. This is done in order to separate solute from solvent. In both forward and reverse osmosis, the solvent molecules are drawn by the concentration gradient, which is caused by the osmotic pressure of each solution. However, this is different from diffusion, which involves the movement of solute molecules.

What is Diffusion

Diffusion is a random movement of molecules from regions of high to low concentration through a selectively permeable membrane. The differential in concentration of solute between the two areas drives the diffusion. However, for osmosis to occur, the concentration differences must be across a semipermeable membrane. This is the difference between osmosis and diffusion.

The 3 Types of Osmosis

There are three different types of osmosis, hyperosmotic, hypoosmotic, and isoosmotic. Hyperosmotic solutions have a higher concentration of solute than other solutions and have a higher osmotic pressure. Hypoosmotic solutions have a lower concentration of solute than other solutions and have lower osmotic pressure. Isoosmotic solutions have the same concentration of solute and the same osmotic pressure.

Osmosis is essential for the health of cells. It helps to maintain the proper levels of water and cellular fluids within living cells, transports nutrients and wastes, regulates the mechanical structure of the cell, and controls cell-to-cell diffusion. Without osmosis, the body would not be able to function properly. For example, if you place an animal cell in a hypotonic solution, it will undergo lysis, meaning the cells will lose their shape and deflate. In plants, osmosis is a key process in plant growth and the absorption of water from the soil.