AP Biology Cell Membrane Structure & Molecule Transport Part 1

Cell Membrane

Amphipathic Phospholipids Hydrophilic head Hydrophobic tail WATER

Amphipathic Proteins Hydrophilic region of protein Hydrophobic region of protein Phospholipid bilayer

Cell Membrane

Membrane Protein Functions Enzymes Signal Receptor ATP Transport Enzymatic activity Signal transduction

Membrane Protein Functions Glyco- protein Cell-cell recognition Intercellular joining Attachment to the cytoskeleton and extra- cellular matrix (ECM)

Cholesterol of the Membrane

Fluid Mosaic Model and Phospholipids Lateral movement (~10 7 times per second) Flip-flop (~ once per month) Movement of phospholipids

Surface Area vs. Volume

Surface Area of the lungs (alveoli)

Digestive Tract Small Intestine averages 23 feet.

Villi and Microvilli on the interior of the small intestine Key Nutrient absorption Microvilli (brush border) Epithelial cells Lacteal Lymph vessel Villi Large circular folds Epithelial cells Blood capillaries Vein carrying blood to hepatic portal vessel Muscle layers Villi Intestinal wall

Excretory Structures

Nitrogenous Waste filtering