2. The Cell Membrane

3. Cell Membrane Basics Function: Controls the passage of materials into and out of a cell Semi-Permeable: only some materials may enter/exit Double layer of phospholipids (bilayer)

4. Phospholipid Composition 3 Parts Polar Head 1) Phosphate Group 2) Glycerol Nonpolar Tails 3) Two chains of fatty acids Arrangement: –Outside: Polar heads –Inside: Nonpolar Tails

5. Phospholipid Bilayer

6. Cell Membrane Contents 1) Cholesterol Molecules: strength 2) Carbohydrates: identification 3) Various Proteins

8. Membrane Proteins Randomly scattered through bilayer Various Functions –Cytoskeleton: internal support –Protein channels: allow objects to pass –Enzymes: speed up chemical reactions –Markers: cell recognition; fight disease

9. Kobe Kuiz 1)Name the 3 parts to a phospholipid? 2)Which part(s) make up the head of a phospholipid? 3)Which part(s) make up the tails of a phospholipid? 4)Which part of phospholipid always seems to be in contact with a watery environment? Why? 5)Draw and label the basic components of the cell membrane. 6)Which membrane protein supports the cell membrane? 7)Which membrane protein allows materials to pass through?