| Osmosis definition | - The movement of water from a region of higher water potential to a region of lower water potential through a partially permeable membrane
- Type of diffusion |
| Water potential meaning | - The potential (likelihood) of water molecules to diffuse into or out of a solution
- Pure water has highest potential of zero |
| Isotonic | - Two solutions having the same water potential |
| Factors that affect the rate of osmosis | - The water potential gradient
- The thickness of the exchange surface
- The surface area of the exchange surface |
| Water potential gradient and osmosis | - The higher it is, the faster the rate
- Difference of water potential decreases until equilibrium is reached |
| The thickness of the exchange surface and osmosis | - The thinner the exchange surface the faster the rate |
| The surface area and osmosis | - The larger the surface area the faster the rate |
| Solutes and water potential | - Adding solutes to pure water will lower water potential
- The water potential of a solution always < zero |
| Using serial dilutions | - Using potato cylinders to find out water potential of tissue
- Uses solutions of different concentrations |
| Serial dilutions process | - Line up 5 test tubes in rack
- Add 10cm3 of 2M sucrose solution to the 1st one
- Add 5 cm3 distilled water to the other tubes
- Using a pipette, take 5cm3 of solution from 1st tube, add to 2nd tube
- Now there's 10cm3 of solution that's half as concentrated as the 1st one
- Repeat process to create solutions of 0.5M, 0.25M and 0.125M |
| Using the solutions to find water potential of potato cells | - Cut potatoes, 1cm in diameter
- Divide chips into 3
- Measure mass, using mass balance
- Place one group into each sucrose solution
- Leave for 20 mins
- Remove + dry them
- Weigh them
- Calculate change in mass for each group
- Plot results on a calibration curve |
| Pinocytosis | - Bulk movement of liquid |
| Phagocytosis | - Bulk movement of solids |
| Cytosis | - This is the BULK movement of molecules in or out of the cell |
| Exocytosis | – This is the bulk movement out of the cell |
| Endocytosis | – This is the bulk movement into the cell |
| Endocytosis description | - An invagination forms in the membrane
- The membrane pinches together to form a vesicle
- The cell membrane reforms
- This process requires energy
- Some endocytosis is RECEPTOR MEDIATED |
