1. Fluid Mosaic Model of the Cell Membrane

2. Function of the Cell Membrane All living cells exist in a aqueous medium The contents of cells are physically separated from the aqueous environment by the cell membrane The cell membrane acts as a selective, dynamic boundary The membrane regulates the passage of molecules and ions into and out of the cell

3. Fluid Mosaic Each layer of the membrane is composed of various macromolecules The phospholipids act as a “scaffolding” in which proteins and other macromolecules are embedded Because the phospholipids are held together by weak intermolecular forces, the molecules can move about freely

4. Phospholipids Phospholipids are diglycerides that are covalently bonded to a phosphate group by an ester linkage. The diglyceride is composed of a glycerol backbone linked to two fatty acids.

6. Cell membranes are composed of two layers of phospholipids in a bilayer arrangement. http://torresbioclan.pbworks.com/w/page/22377072/cell%20membrane%20-%20team%20sMART

8. Fluid Mosaic Model A mosaic is a structure made up of many different parts. The plasma membrane is composed of different kinds of macromolecules: integral proteins peripheral proteins glycoproteins phospholipids glycolipids cholesterol

9. Integral Membrane Proteins Regions of integral membrane proteins penetrate the hydrophobic regions of the phospholipid bilayer. The presence of these proteins gives the membrane specific functions.

10. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellMembranes.html

11. http://www.ks.uiuc.edu/Research/lacY/

12. http://plantphys.info/plant_physiology/basiccytology1.shtml

13. Examples of integral membrane proteins Na+ - K+ ATPase glucose permease hormone receptors ion channels and gates histocompatibility antigens certain enzymes of the electron transport chains gap junction proteins

14. Peripheral Membrane Proteins Peripheral membrane proteins are associated with membranes but do not penetrate the hydrophobic core of the membrane. They are often found in association with integral membrane proteins. An example of peripheral membrane protein is the cytochrome C in the electron transport chain.

15. http://tonga.usip.edu/gmoyna/biochem341/lecture30.html

16. Glycoproteins Glycoproteins are proteins that are covalently bonded to carbohydrates. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/Glycoproteins.html

18. Glycolipids Glycolipids are membrane components composed of lipids that are covalently bonded to monosaccharides or polysaccharides. One type of glycolipid found in human red blood cells is involved in the ABO blood type antigens.

19. Glycolipids http://www.ncbi.nlm.nih.gov/books/NBK26871/

20. Cholesterol Cholesterol is a component of cell membranes and involved in membrane fluidity It helps to keep human cell membranes from being too fluid at body temperature

21. Function of Proteins in Cell Membranes Transport: proteins play an essential role in transporting substances across the cell membranes Reaction catalysts: enzymes in the cell membranes carry out chemical reactions Cell recognition: the carbohydrate chains that protrude from glycoproteins allow cells to recognize each other Signal reception and transduction: receptor proteins bind to signal molecules such as hormones and initiate a cellular response