Biology Controlled Assessment
Osmosis is the diffusion of water from a high concentration to a low concentration through a semi-permeable membrane.
This process does not require energy and is known as passive transport, it works through pressure to reach equilibrium, i.e. the same concentration on both sides.
There are three main types of solutions in regards to osmosis:
-A hypotonic solution is a solution with a lower concentration of solutes compared to another. A cell in a hypotonic solution has a higher concentration of solutes than the surrounding solution, causing water to flow into the cell. Cells can burst (cytolysis) in some cases.
-A hypertonic solution is a solution with a higher concentration of solutes compared to another. A cell in a hypertonic solution has a lower concentration of solutes than its surroundings, leading to a decrease of water in the cell.
-Isotonic solution is a solution that has no difference in solute concentration across the semi permeable membrane, therefore has no movement of water across the membrane.
Strategy- S (a)
There are several factors that can control the rate of osmosis:
Temperature - The higher the temperature, the faster the movement of water molecules across the semi permeable membrane, therefore an increased rate of osmosis.
Surface area- the greater the surface area of a cell and it's membrane the faster the rate of osmosis. This is due to the water particles having a larger area of semi-permeable membrane to pass through, speeding up the rate of osmosis.
Solute Concentration and water potential (Ã°ÂÂÂ)- The higher the concentration of the solute in a solution, than that of the cell, the faster the rate of osmosis will occur. Similarly the lower the water potential (Ã°ÂÂÂ) of the solution, than that of the cell, the faster the...