| What is Diffusion? | Diffusion is just the movement of particles from a high concentration to a low concentration |
| What states can it happen and why? | Liquid and Gases. This is because the particles are free to move around randomly. |
| What in the cell is used to allow diffusion and is there a limit? | The Cell Membrane. They allow stuff in and out as well as keeping the cell together. The size has to be small however. eg Glucose |
| So how does diffusion work? | Lets take oxygen molecues for example. The cell has a low concentration of oxygen while the outside has a high concentration. The particles spread out and go towards the low concentration [the cell] The cell spends no energy and gets the resources it needs. |
| What is the Diffusion gradient? | This is just showing the particles concentration and destination in picture. |
| What is Active Transport? | This is the opposite of Diffusion. This is moving particles from a low concentration to a high concentration. Energy is required for this process as the particles want to spread out and not go in. |
| Examples of Active Transport? | Plants use this to get the minerals via the soil. |
| What is Osmosis? | This is like diffusion, but with water molecules moving from a higher concentration to a lower concentration. |
| Is their any differences with Osmosis | Yes. The membrane has to be semi-permeable membrane/ partially permeable membrane |
| What is water potential? | This is saying if its a high or low concentration. High water potentital=high concentration of water molecules. Pure water has the highest water potential |
| What are Turgid cells? | They are located in Plants. This links in with water potenital in the soil. If its high, then the cell becomes turgid and the cell insides push against the cell wall. This helps support the plant tissues.
If the soil has a low water potential, then the cell becomes flaccid, where the cell walls retract. They don't loose their shape, as their inelastic cell wall keeps it in position. |
| Does Osmosis increase mass? | It can. If you put a potato [for example] in a pure water solution, where the outside has a higher concentration then the insides, water molecules will be drawn into the potato therefore adding the mass onto the cell. It can be seen visually too.
The opposite can happen. If the solution has got a lower water concentration then water molecules will go out and therefore will lower the mass. |
| How would you find out the percentage change in mass? | You would do:
Final mass-Intial mass
---------[Divide]-------- x 100.
Inital mass |
| Can the rates of Diffusion, Osmosis and Active transport be affected? | Yes
Surface area: Volume ratio. The smaller a object can be, the higher the ratio is. This can help it diffuse more effectivley and quicker
Temperature: When it gets hotter, particles gets more energy, kinetic energy. They move around quicker which means they can go in/out quicker
Concentration Gradient: If the line is steeper, the particles quantity will be increased in terms of moving across. |
