CELL (PLASMA) MEMBRANE Chapter 4 Pg. 77-78

Homeostasis Balanced internal conditions of cells Maintained by cell membrane controlling what enters or leaves cell.

Cell (Plasma) Membrane Function: Protective barrier Semi-permeable: Regulated transport of molecules in and out of cell

Cell (Plasma) Membrane Function: Protective barrier Semi-permeable: Regulated transport of molecules in and out of cell Allow cell recognition Interact with the environment

Structure Phospholipid Bilayer - Two layers of phospholipids

Structure Phospholipid Bilayer - Two layers of phospholipids Phospholipid contains: 2 fatty acid chains that are nonpolar (hydrophobic) Polar head (hydrophilic)

Structure Phospholipid Bilayer - Two layers of phospholipids Phospholipid contains: 2 fatty acid chains that are nonpolar (hydrophobic) Polar head (hydrophilic) Fatty acid tails create a hydrophobic center

Membrane Structure 2. Membrane Proteins-embedded in the lipid layer a. Integral Proteins: extend through both sides of membrane

Membrane Structure 2. Membrane Proteins-embedded in the lipid layer a. Integral Proteins: extend through both sides of membrane Receptor Proteins: binds to substances outside the cell

Membrane Structure 2. Membrane Proteins-embedded in the lipid layer a. Integral Proteins: extend through both sides of membrane Receptor Proteins: binds to substances outside the cell Transport (channel) Proteins: Aids in moving substances across membrane Glycoproteins (with Carbs): cell identification

Membrane Structure 2. Membrane Proteins-embedded in the lipid layer b. Peripheral Proteins: only on one side of membrane -Enzymes (assist in chemical reactions)

Membrane Structure 3. Cholesterol in bilayer for strength

Blue Biology Textbook Draw Figure 4-10 Pg. 77 Draw Figure 4-11 Pg. 78 Cell membrane coloring