What Is Osmosis And Diffusion?

Is this information on osmosis/diffusion correct?

• I had to write this as an introduction for a prac. I find osmosis confusing so could somebody tell me if what I have written is correct! thanks :D Diffusion is the movement of gas or liquid particles from an area of high concentration to an area of low concentration. This is caused by the constant movement of particles and requires no energy. When referring to cells, diffusion occurs across the semi-permeable phospholipid bi-layer. Particles that often diffuse in and out of cells are O2 and CO2. Osmosis is the diffusion of water from an area of low solute concentration to an area of high solute concentration across a membrane. A solution is a liquid comprised of a solute dissolved and uniformly distributed throughout a solvent [1]. An example of a solution is sucrose (C12H22O11), a solute, dissolved in water (H2O), a solvent. Osmosis can occur in both plant and animal cells. If the concentration of the solutes inside the cell and outside the cell is the same, there will be particle movement but no net loss or gain. These solutions are Isotonic. If the concentration of the solute outside the cell were higher than the solute inside the cell, water would diffuse out of the cell until the solutions reach equilibrium. The solution inside the cell is hypotonic. When the solution diffuses out of the cell, the cell shrinks. If the concentration of the solute outside the cell were lower than the solute inside the cell, water would diffuse into the cell until the solutions reach equilibrium. The solution inside the cell is hypertonic. When the solution diffuses into the cell, the cell swells.

• Answer:

  This looks like a good start, I think you have hypertonic and hypotonic solutions backwards. Tonicity describes how a cell reacts to a certain solution. So when you refer to a solution being hypertonic, hypotonic or isotonic, it is the solution outside of the cell that you should be referring to. If a cell is placed into a hypertonic solution it means that there is a higher concentration of solutes outside of the cell and water will diffuse out of the cell, causing it to shrink. If a cell is placed in a hypotonic solution, that means that there is a higher solute concentration inside of the cell than outside, so water will diffuse into the cell, causing it to swell.