Movement of substances Flashcards
What is diffusion?
The random movement of particles from an area of high concentration to an area of low concentration
What affects diffusion?
Temperature, Concentration gradient, distance and surface area
What is Osmosis?
The net diffusion of free water molecules from a high concentration to a low concentration across a semi permeable membrane
What are Free water molecules?
Water molecules that are not joined to another substance e.g. when a sugar dissolved in water, the sugar binds to the water molecules meaning that they are not free anymore
What is a partially permeable membrane?
A membrane that only allows certain particles through. I.e. if a particle is too big, it cannot fit through the membrane, but if a particle is small enough it can fit through to the other side of the membrane
What is water potential?
The measure of the concentration of free water molecules in a solution
What is an isotonic solution?
when the solution outside the cell has the same water potential as the inside cell. Molecules don’t move
What is a hypotonic solution?
when the solution outside the cell has a higher water potential than the inside of the cell. Molecules move in
What is a hypertonic solution?
when the solution outside the cell has a lower water potential than the inside of the cell. Molecules move out.
What is active transport?
The movement of molecules from an area of low concentration to an area of high concentration using ATP
