Cell Membrane Structure and Function Biology Ch 7

Cell Membrane Structure and Function Biology Ch. 7 -3

Recall: Macromolecules BIG biological molecules • Made of smaller parts Monomers Carbon-based (organic) • • Carbohydrates Nucleic acids Proteins Lipids

Lipids Monomer? • Glycerol head • Fatty acid tail Used for: • Long term energy storage • Insulation • Major component of membranes • Signaling molecules and hormones Examples: • Fats, oils, waxes Found in: • All the good tasting foods

Cellular Biology Review Cell membranes surround: • Prokaryotic & Eukaryotic cells

Cell Membrane Functions 1. 2. 3. Regulate passage of material into/out of cell Provide limited support & protection to cell Communicate with other cells

Detailed Structure Made of Phospholipids • phosphorus (hydrophilic) “head” • lipid (hydrophobic) “tail”

Detailed Structure Phospholipid bilayer • a double layer of phospholipids

Other Structures Protein Channels • allows large molecules to pass through Carbohydrate antennae • picks up messages from outside the cell Cholesterol • lipids that prevent freezing

Cell Membrane Structures Carbohydrate antenna Phospholipid bilayer Protein channels

Cell Membrane Properties The membrane is a fluid-mosaic: • Flexible; not rigid • Semi-permeable: picky about what enters/exits the cell

Membrane Molecules Small Molecules move through bilayer • H 2 O, CO 2 & O 2 Large Molecules move through proteins • C 6 H 12 O 6 (GLUCOSE)

Fluid Mosaic Model http: //www. wiley. com/legacy/college/boyer/ 0470003790/animations/membrane_transp ort/membrane_transport. htm http: //www. susanahalpine. com/anim/Life/m emb. htm