Sixth Class: Cell Wall Structure

In this class we examined how diffusion and osmosis work at a cellular level. Molecules trying to get through the call wall must either be non-polar and pass through the bi lipid layer, or get "ferried" across by a protein.  Polar molecules such as H2O cannot slip all the way through the bi-lipid layer because when they reach the second layer the polarities repel and it is shot back out.  For non polar molecules that are not too large, this is no problem and they slip through without going through a protein.  For the polar molecules to get into cells, this is what they must do.  Certain proteins will accept certain molecules while others will let any molecules of the correct size pass through easily.  These proteins are scattered all over the cell wall to pick up molecules as they come in.  They serve as the GATEKEEPERS  for the cell.  The carbohydrates on cells reach out and grab connect with other cells.  Messages such as pain, are sent through the body by these connections chemically.  Thus a body of cells works together by connecting cell membranes.