| Cell membranes have a fluid mosaic. what is it? | the phospholipid layer is fluid because the phospholipids are always moving. the proteins are scattered in a mosaic pattern |
| functions of the cell membrane | 1. transport
2.digestion
3. immune responses |
| 3 factors molecules have to be to cross the phopholipid bi layer | 1. small
2. non polar
3. lipid soluble |
| Diffusion | high to low concentration
no energ req |
| Facilitated diffusion | polar mols
channel or carrier protein
high to low |
| active transport | low to high so against conc g
requires energy - atp
carrier protein ( have specific binding site that the molecule joins too , changing shape of the binding site so the molecule can be transported ). |
| co transport | 2 mols transported together
fd= high to low |
| factors affection the rate of diffusion | - temp- kinetic energy
- number of proteins
-conc gradient
-diffusion pathway distance
-surface area |
| osmoisis | the netmovement of water from an area of high water potental to low |
| How do polar and lipid insoluble molecules cross the the membrane | Transport proteins - channel or carrier |
| Describing transport keywords | 1. Concentration gradient ( high to low / low to high (atp required )
2. Transport protein ( channel or carrier )
3.ATP require aka active transport |
| Phospholipid bilayer structure | extrinsic . intrinsic proteins
cholesterol |
