3.2 movement of substances across the plasma membrane in everyday life

3.2 movement of substances across the plasma membrane in everyday lifeHypotonic, hypertonic and isotonic solutionIsotonic solution :Solution A and Solution B have the same solute concentration

Hypertonic solution : Solution A is hypertonic to solution B if solution A has a higher solute concentration

Hypotonic solution:

Solution A is hypotonic to solution B if solution A has lower solute concentration than solution B

Effects of hypotonic, hypertonic and isotonic solutions on plant cell

crenationhaemolysis

Plasmolysed (flaccid)turgidLiquid/solutionDistilled water (hypotonic solution)5% Sucrose solution (isotonic solution)30% Sucrose solution (hypertonic solution)Drawing

Description Bent outwardsNo changeBent inwardsinferenceWater had entered the cells vacuoles by osmosis, so cells became turgid and expandedNo net movement of water by osmosis, so the strip maintained its shapeWater had left the cell vacuoles and the cells became flaccidFlaccid cells pulled the epidermis, bending the strip inwardsPhenomenon of wilting in plantsExcessive use of chemical fertilizers release huge amount of ions, such as phosphates, nitrates, calcium, magnesium, and sulphur into soil

Increase solute concentration but decrease water molecules concentration in soil

Water molecules diffuse from the cell sap into soil water by osmosis

Cell plasmolysed, lose turgidity & support = WILT Preservation of foodConcentrated salt solution has a high concentration of solute (Na+ and Cl- ions) and very low concentration of water moleculesAll water molecules inside drawn out by osmosisWithout water, bacteria and water cannot survive