| What 2 types of molecules are plasma membranes made of? | protein and phospholipids |
| What term describes the head of a phospholipid in terms of it's reaction to water? | hydrophilic (water loving) |
| What term describes the tail of a phospholipid in terms of it's reaction to water? | hydrophobic (water hating) |
| Name the area inside a cell | intracellular |
| Name the area inside a cell | extracellular |
| A cell membrane is selectively permeable, what does it select based on? | size |
| Selectively permeable meaning | it allows some molecules to pass from one side to the other while other molecule are unable to pass through it |
| examples of molecules that move by diffusion | carbon dioxide, oxygen, glucose |
| examples of molecules that don't pass through an SPM by diffusion | food, protein, starch |
| What is a bilayer? | a double layer of closely packed atoms or molecules |
| Fluid Mosaic | describes how a cell membrane looks and functions |
| test for glucose | benedict's reagent turns brick red |
| Why do cells have a membrane? | so they can have different intracellular conditions from extracellular conditions |
| Why transport? (in green plant cells) | they need to photosynthesise so they require carbon dioxide to enter the cell |
| passive transport | high to low concentration, does not require energy |
| active transport | low to high concentration, does require energy |
| passive transport examples | diffusion and osmosis |
| diffusion | the movement of particles from an area of high concentration to an area of low concentration until evenly spread |
| result of diffusion | even distribution of that type of particle |
| osmosis | the movement of water from an area of high water concentration to an area of low water concentration through a selectively permeable membrane |
| When is a cell fully turgid? | in water |
| fully turgid | large vacuole, cell membrane pushed against cell wall, cell wall prevents cell from bursting |
| When is a cell plasmolysed? | in a salt solution (in a concentrated solution) |
| plasmolysed | small vacuole, cell membrane shrunken away from cell wall, cell wall prevents collapse |
| How is tissue described when lots of cells are plasmolysed? | flaccid |
| What happens to a red blood cell in water? | water would enter the cell by osmosis, it would swell up then burst |
| hypertonic | a solution which effectively has a LWC because there is a lot of solute dissolved in it |
| hypotonic | a solution which effectively has a HWC because there is very little solute dissolved in it |
| isotonic | refers to two solutions having the same water concentration |
| What are the terms hypertonic, hypotonic and isotonic used for? | to compare water concentrations of fluids on either side of an SPM |
| solute | the thing that gets dissolved |
| solvent | what the solute gets dissolved in - the liquid that does the dissolving |
| solution | the product of a solute dissolving in a solvent |
| Why does amoeba not burst? | it has a contractile vacuole which sucks up the water and squirts it back out |
| Where does the energy needed for active transport come from? | the ATP - which comes from respiration |
