Explanation:
Hello!
Tonicity is a measure of the effective osmotic pressure gradient, it is the relative concentration of solutes dissolved in solution. If you compare two solutions separated by a semipermeable membrane, tonicity is influenced only by solutes that cannot cross the membrane, since the solutes that freely cross the membrane will always equilibrate in equal concentrations on both sides of it, they do not affect the tonicity of the solutions.
You can find three types of solutions classified concerning another solution:
1. Isotonic: The concentration of solutes is equal in both solutions. There is no diffusion of solvent (water)
2. Hypotonic: The concentration of solutes is lower than the other solution. If a cell is in a hypotonic solution, due to the osmotic pressure the water will diffuse into the cell (its tonicity is greater than the tonicity of the solution), the cell will appear bloated and if the gradient is large enough the cell suffers rupture due to the excess of water.
3. Hypertonic: The concentration of solutes is greater than the other solution. Due to osmotic pressure, the water diffuses from the solution with less tonicity to the solution with greater tonicity. If a cell is put in a hypertonic solution the water will diffuse outside the cell, this produces a process called crenation which is the destruction of the cell due to dehydration.
The direction of diffusion is always determined by the concentrations in both compartments, it will always diffuse from the compartment with less solute concentration to the compartment with higher solute concentration.
Box 1
Inside the circle is 10% of solute, to see what is the % the calculation is:
100% - 10%= 90% H₂0
Outside the circle is 15% of solute, so the % of water is:
100% - 15%= 85%
The concentration of solutes in the circle is less than the concentration of the solution outside, it means that the solution outside is hypertonic.
The water will flow from "Inside" → "outside"
Box 2
Inside the circle is 18% of solute, to see what is the % the calculation is:
100% - 18%= 82% H₂0
Outside the circle is 10% of solute, so the % of water is:
100% - 10%= 90%
The concentration of solute outside the circle is less than the concentration inside the circle, the solution is hypotonic.
The water will flow from "outside" → "Inside"
Box 3
Inside the circle is 85% of solute, to see what is the % the calculation is:
100% - 85%= 15% H₂0
Outside the circle is 95% of solute, so the % of water is:
100% - 95%= 5%
The concentration outside the circle is less than the concentration inside it, the solution is hypotonic.
The water will flow from "outside" → "Inside"
Box 4
Inside the circle is 15% of solute, to see what is the % the calculation is:
100% - 15%= 85% H₂0
Outside the circle is 15% of solute, so the % of water is:
100% - 15%= 85%
The concentration outside the circle is equal to the concentration inside it, the solution is isotonic.
The Δdiffusion of water is cero: "outside" ⇄ "Inside"
Box 5
Inside the circle is 98% of solute, to see what is the % the calculation is:
100% - 98%= 2% H₂0
Outside the circle is 95% of solute, so the % of water is:
100% - 95%= 5%
The concentration of the solution outside the circle is higher than the concentration inside the circle, so the solution is hypertonic.
The water will flow from "outside" → "Inside"
Box 6
Inside the circle is 83% of solute, to see what is the % the calculation is:
100% - 83%= 17% H₂0
Outside the circle is 80% of solute, so the % of water is:
100% - 80%= 20%
The concentration of the solution inside the circle is less than the concentration outside the circle, so the solution is hypertonic.
The water will flow from "outside" → "Inside"
I hope it helps!
