| what is simple diffusion? | net movement of molecules from high conc to low conc down the conc gradient |
| where can diffusion happen | through the cell membrane (phospholipid bi-layer) |
| how is simple diffusion limited though cell membranes | if it is too big it cant move into or out of the cell, also the phospholipid bi layer has hydrophobic parts (fatty acids) meaning that hydrophilic molecules cannot passthrough. |
| why else might molecules not be able to pass through the cell membrane through simple diffusion | if it is a charged ion, it cannot move through. |
| so how do charged, polar or large particles pass through the hydrophobic bi layer? | through facilitated diffusion. |
| why can't h20 pass through the cell membrane | because it has a dipole (charged) |
| so how can we let h20 pass through. | through a protein channel |
| what are the protein channels that allow for water to move through called? | aquaporin |
| how can h2o pas through aquaporin | as it is protected by the hydrophobic parts of the bi layer |
| what do we do if we need to transport sodium ions and what not | we use transport proteins |
| what do transport proteins normally have | a gate so that it can open and close to let the ions through |
| what is the niche of the transport protein | they are always specific |
| what happens as the ions like Na+ travels through the transport protein. | it moves down the concentration gradient. |
| what is a carrier protien | it is a type of transport protein |
| what happens when a molecule binds with the carrier protein. | it will change shape to allow the molecule inside it to move through. It CARRIES across the molecule |
| what are tranport proteins and carrier proteins all examples of? | they are all examples of facillitated diffusion. meaning that the substances move down the concentration gradient, passive and not using ATP and they use transport proteins |
