The Movement of Substances Flashcards
Define diffusion:
The net movement of particles from an area of high concentration to an area of low concentration.
Define osmosis:
The movement of water molecules from an area of higher water concentration to an area of lower water concentration through a partially permeable membrane.
Define active transport:
The movement of particles against a concentration gradient using energy released during respiration.
What are the 4 factors affecting the movements of substances?
1) Surface area to volume ratio.
2) Distance.
3) Temperature.
4) Concentration gradient.
How does surface area to volume ratio affect the movement of substances?
The rate of diffusion, osmosis and active transport is higher in cells with a larger surface area to volume ratio.
How does distance affect the movement of substances?
The shorter the distance, the faster things will move in and out of cells.
How does temperature affect the movement of substances?
As temperature increases, cells move in and out of cells faster as they gain more energy.
How does concentration gradient affect the movement of substances?
The bigger the concentration gradient, the faster substances will move in and out of cells.
This only increases the rate of diffusion and osmosis, not active transport.
What living and non-living things do you use to investigate osmosis?
Living: potato cylinders in different sugar solutions.
Non-living: Sugar solution in a thistle funnel with visking tubing fixed over the end in a beaker of pure water.
What non-living things do you use to investigate diffusion?
Phenolphthalein: our pH indicator
Agar jelly cubes: have our indictor in them
Sodium hydroxide: Also put into the cubes to make them turn pink (alkali)
Hydrochloric acid: In a beaker with the agar cubes in it too to diffuse into the cubes and turn them colourless.
What is needed to carry out active transport?
Carrier proteins.
