1. The Cell Membrane Cell membranes are composed of two phospholipid layers.

2. The Cell Membrane Cell membranes are composed of two phospholipid layers.  The cell membrane has two major functions.

3. The Cell Membrane Cell membranes are composed of two phospholipid layers.  The cell membrane has two major functions.  forms a boundary between inside and outside of the cell cell membrane outside cell inside cell

4. The Cell Membrane Cell membranes are composed of two phospholipid layers.  The cell membrane has two major functions.  forms a boundary between inside and outside of the cell  controls passage of materials cell membrane outside cell inside cell

5. The Cell Membrane Cell membranes are composed of two phospholipid layers.

6. The Cell Membrane cell membrane Cell membranes are composed of two phospholipid layers.  The cell membrane is made of a phospholipid bilayer.

7. The Cell Membrane cell membrane Cell membranes are composed of two phospholipid layers.  The cell membrane is made of a phospholipid bilayer.  There are other molecules embedded in the membrane. protein cholesterol protein carbohydrate chain protein channel

8. The Cell Membrane cell membrane Cell membranes are composed of two phospholipid layers.  The cell membrane is made of a phospholipid bilayer.  There are other molecules embedded in the membrane.  The fluid mosaic model describes the membrane. protein cholesterol protein carbohydrate chain protein channel

9. The Cell Membrane Cell membranes are composed of two phospholipid layers.

10. The Cell Membrane Cell membranes are composed of two phospholipid layers.  The cell membrane is selectively permeable. Some molecules can cross the membrane while others cannot.

11. The Cell Membrane Cell membranes are composed of two phospholipid layers.  The cell membrane is selectively permeable. Some molecules can cross the membrane while others cannot.

12. The Cell Membrane The cell membrane has proteins embedded in it.  There are four main types of membrane proteins.  Cell-surface marker  Enzymes  Transport protein  Receptor protein  Proteins have polar and nonpolar sections.  The polar sections of the protein attach to the polar heads.  The nonpolar sections of the protein attach to the nonpolar tails.

13. The Cell Membrane Cell-surface markers identify what type of cell it is.  Many cell-surface markers are glycoproteins.  Glycoproteins are a combination of a protein with a polysaccharide attached.  Auto-immune diseases such as lupus are caused by the body mis- identifying the glycoprotein on a cell.  This causes the white blood cells to attack the body’s own cells.

14. The Cell Membrane Enzymes are also embedded in the cell membrane.  These membranes speed up chemical reaction within the cell. Transport proteins help substances move across the cell membrane.  Some molecules are too big to move between the lipid bilayer, and therefore have to be allowed into a cell through the transport protein.  Some transport proteins require ATP to open.

15. The Cell Membrane Chemical signals are transmitted across the cell membrane.  Receptors bind with ligands and change shape.  There are two types of receptors.

16. The Cell Membrane Chemical signals are transmitted across the cell membrane.  Receptors bind with ligands and change shape.  There are two types of receptors.  intracellular receptor

17. The Cell Membrane Chemical signals are transmitted across the cell membrane.  Receptors bind with ligands and change shape.  There are two types of receptors.  intracellular receptor  membrane receptor