2. CELL MEMBRANE STRUCTURE AND FUNCTIONS By. Dr Nazish

3. Learning Objectives 1. The bilayer structure of plasma membrane 2. Types of lipids in the membrane: physiological significance 3. Physiological importance of proteins in the plasma membrane 4. Types of carbohydrates: physiological importance 5. Selective permeability characteristics of the plasma membrane.

4. Lipid bilayer Intracellular fluid Extracellular fluid

5. Choline Phosphate Glycerol Fatty acid Head (polar, hydrophilic) Tails (nonpolar, hydrophobic) - = Negative charge on phosphate group - Lipid bilayer is phospholipids

6. Lipid bilayer ICF (water) ECF (water) Polar heads (hydrophilic) Nonpolar tails (hydrophobic) Polar heads (hydrophilic) Phospholipids form a bilayer That has a hydrophobic interior. This interior is sandwiched between hydrophilic inner and outer surfaces.

7. Functions of the lipid bilayer Cholesterol : allows the membrane to be fluid. - Forms the basic structure of the membrane. - Hydrophobic interior is a barrier to water- soluble substances - allows diffusion of fat soluble substances

8. Extracellular fluid Lipid bilayer Intracellular fluid Dark line Light space Appearance using an electron microscope Dark line Glycoprotein Glycolipid Carbohydrate chain Channel Various membrane proteins Cholesterol molecule Phospholipid molecule

9. Functions of plasma membrane Channel proteins

10. Functions of membrane proteins Carrier proteins

11. Functions of plasma membrane Receptor proteins

12. Functions of plasma membrane Docking marker acceptors

13. Functions of plasma membrane cell adhesion molecules

14. Functions of cell membrane Self identification markers

15. Membrane- bound enzymes ReceptorCarrier molecules molecules Functions of membrane proteins Channels Channels Docking- marker acceptors Cell adhesion molecules Cell identity markers

16. Channels: span the membrane as water-filled pores Carrier molecules Receptor sites: proteins that bind with specific molecules Docking-marker acceptors (on inner surface for secretory vesicles) Filamentous meshwork (cytoskeleton) Membrane-bound enzymes Cell adhesion molecules : protrude from surface Cell identity markers in conjunction with carbohydrates Functions of membrane proteins.

17. CHO containing Surface markers involved in tissue growth. Cell identity markers in conjunction with proteins Functions of membrane carbohydrates.

18. THANK YOU AND HAVE A NICE DAY