Thursday, October 14, 2010

sections 6.2 and 6.3 reflection

This is what I learned about what the function of membranes is. I learned that the plasma membrane is composed of phospholipids. This plasma membrane is what holds the contents of a eukaryotic cell inside the cell. I learned that proteins are what allows the membranes to perform certain functions and these proteins also help cells communicate with one another. I also learned that membranes can permit certain substances and deny others access to the interior of the cell.
What I have found difficult about what I have studied are the contents in section 6.3. Some concepts I can understand but others such as hypertonic, hypotonic, and isotonic go right over my head. Also, I simply have no idea how to understand the pictures on pg. 120. After reading it several times, the whole idea seems to completely evade me.
Structure is related to function in cell membranes because membranes give the cell its rigid form and the membrane also serves as a regulator, allowing only certain substances inside the cell. This mean that the plasma membrane is very fluid and is constantly moving, allowing for substances to pass through in the first place. This membrane or boundary, holds many proteins that perform specific functions for the cell. Also, because the unique structure of the plasma membrane, the proteins that are lodged in the membrane are able to communicate with other cell's proteins.


  1. 6.3 is tough, but as you read you must relate the pictures to the reading. Compare and contrast what is happening in each picture. Notice the differences. Good job.

  2. a hypertonic solution is a solution with more solute than the cell which causes the H2O in the cell to rush out of the cell into the solution. a hypotonic solution is just the opposite, where there is more solute in the cell than in the solution so the H2O rushes into the cell cause the cell to expand and possibly burst, this is an ideal state for a plant cell. an isotonic solution is where the amount of solute is equal in the cell and the solution so the same amount of H2O is coming in as it is leaving the cell, this is the ideal state for a animal cell.