Membrane Structure & Molecule Transport Part 2 AP Biology Membrane Structure & Molecule Transport Part 2

Cell Membrane

Cellular Transport 2 Types 1.) Active Transport *Requires Energy *Goes against concentration gradient 2.) Passive Transport

Active Transport Cytoplasmic Na+ bonds to the sodium-potassium pump EXTRACELLULAR FLUID [Na+] high [K+] low Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ [Na+] low [K+] high ATP P Na+ P CYTOPLASM ADP Cytoplasmic Na+ bonds to the sodium-potassium pump Na+ binding stimulates phosphorylation by ATP. Phosphorylation causes the protein to change its conformation, expelling Na+ to the outside. K+ K+ K+ K+ K+ P P K+ Extracellular K+ binds to the protein, triggering release of the phosphate group. Loss of the phosphate restores the protein’s original conformation. K+ is released and Na+ sites are receptive again; the cycle repeats.

Proton pumps

Proton pumps and co-transport

Phagocytosis & Pinocytosis

RECEPTOR-MEDIATED ENDOCYTOSIS . RECEPTOR-MEDIATED ENDOCYTOSIS Coat protein Receptor Coated vesicle Coated pit Ligand A coated pit and a coated vesicle formed during receptor- mediated endocytosis (TEMs). Coat protein Plasma membrane 0.25 µm

Cellular Transport 2 Types 1.) Active Transport *Requires Energy *Goes against concentration gradient 2.) Passive Transport- No energy needed *Goes with concentration gradient (required) *ALWAYS A TYPE OF DIFFUSION

Diffusion

Fluid Mosaic Model and Phospholipids Lateral movement (~107 times per second) Flip-flop (~ once per month) Movement of phospholipids

Facilitated Diffusion EXTRACELLULAR FLUID Channel protein Solute CYTOPLASM

“Grabber” Transport proteins Carrier protein Solute

Osmosis

. Hypotonic solution Isotonic solution Hypertonic solution Animal cell H2O H2O H2O H2O Lysed Normal Shriveled Plant cell H2O H2O H2O H2O Turgid (normal) Flaccid Plasmolyzed

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 Vein carrying blood to hepatic portal vessel Microvilli (brush border) Blood capillaries Epithelial cells Muscle layers Epithelial cells Large circular folds Lacteal Villi Lymph vessel Villi Intestinal wall

Excretory Structures

Nitrogenous Waste filtering

Surface Area vs. Volume