3.3 – The Cell Membrane:

1. 3.3 – The Cell Membrane:

2. Cell membranes are composed of two phospholipid layers.

3. cell membrane • Cell membranes are composed of two phospholipid layers. • The cell membrane has two major functions.

4. 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 outside cell inside cell

5. 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 • Regulates which materials enter and leave the cell outside cell inside cell

6. Cell membranes are composed of two phospholipid layers.

7. cell membrane • Cell membranes are composed of two phospholipid layers. • The cell membrane is made of a phospholipid bilayer.

8. carbohydrate chain protein cell membrane cholesterol protein protein channel • 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.

9. carbohydrate chain protein cell membrane cholesterol protein protein channel • 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.

10. Phospholipids: polar “heads” and nonpolar “tails” Charged Phosphate Group Glycerol Two fatty acid chains Hydrophilic head Hydrophobic tail

11. Cell membranes are composed of two phospholipid layers.

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

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

14. Chemical signals are transmitted across the cell membrane. • Receptors are proteins that detect a signal molecule and perform an action in response.

15. Chemical signals are transmitted across the cell membrane. • Receptors bind with ligands and change shape. • There are two types of receptors. • 1. Intracellular receptor -inside the cell -binds to ligands that can enter cell

16. Chemical signals are transmitted across the cell membrane. • Receptors bind with ligands and change shape. • There are two types of receptors. • intracellular receptor • 2. Membrane receptor -inside the membrane -Binds to ligands that can not enter cell