Chapter 7.3: Structure of the Cell Membrane

 How is a colander (sifter) similar to a cell membrane? Read on to find out.  1. What are some things that can pass through a colander (sifter)?  2. What are some things that cannot pass through a colander (sifter)? Why is it important to keep these things from moving through the colander (sifter)?  3. The cell is surrounded by a cell membrane, which regulates what enters and leaves the cell. Why is it important to regulate what moves into and out of a cell? In or Out?

Parts of Cell Membrane  Phospholipids (lipids with phosphate groups)  Proteins

Phospholipids  Two parts a polar head group and a nonpolar tail group Nonpolar tail Polar head  The phospholipids line up next to each other to form a lipid bilayer (2 layers)

 The nonpolar region acts as the barrier and separates the cell from its environment.

Proteins  Types of proteins 1. Channel proteins 2. Receptor proteins 3. Markers

 Channel Proteins:  Act like tunnels to allow specific molecules through Receptor Proteins: Transfers information from outside to inside the cell Triggers a response inside the cell by a molecule attaching to outside of cell Markers: Identifies the cell– “Name tag”

References  membrane.htm membrane.htm membrane.htm  ee/BIOBK/BioBookCELL2.html#The%20C ell%20Membrane ee/BIOBK/BioBookCELL2.html#The%20C ell%20Membrane ee/BIOBK/BioBookCELL2.html#The%20C ell%20Membrane 

  2.html#The%20Cell%20Membrane 2.html#The%20Cell%20Membrane 2.html#The%20Cell%20Membrane 