Active Transport Honors Biology Active Transport Cells may

Active Transport Honors Biology

Active Transport § Cells may need to move molecules against concentration gradient u u Uses protein “pumps” shape change transports solute from one side of membrane to other conformational change “costs” energy = ATP high u ATP low Honors Biology d f “The Doorman”

Protein Pumps § “Pumps” are a special type of transport proteins called carrier proteins. § Carrier proteins are used to move substances against their concentration gradient (from areas of high concentration to areas of low concentration). Honors Biology

More on Carrier Proteins u Carrier proteins bind to substances on one side of the membrane and release them on the other side. § REMEMBER: Carrier proteins are used in both passive and active transport. What is the difference? § Particles that are actively “pumped”: sodium, potassium, calcium, and hydrogen ions. Honors Biology

Carrier Proteins Honors Biology

Honors Biology

The Sodium-Potassium Pump § The Sodium-Potassium Pump admits ions needed for important biological processes u Pumps 3 sodium (NA+) out, and 2 potassium (K+) in § Both ions are being “pumped” against concentration gradient using ATP – Important for important glucose transport – Important for regulating water Honors Biology

Sodium-Potassium Pump Honors Biology

Transport Review § Passive Transport u Diffusion down concentration gradient (high low) § Simple diffusion – diffusion of very small, nonpolar, hydrophobic molecules – Through membrane » high low concentration gradient » Osmosis § Facilitated diffusion – diffusion of polar, hydrophilic molecules – through protein channels » high low concentration gradient » Ion channels § Active transport u u u Diffusion against concentration gradient (low high) uses a protein pumps (Sodium-Potassium) requires ATP Honors Biology ATP

Transport summary simple diffusion facilitated diffusion active transport Honors Biology ATP

What about large molecules? § Moving large molecules into & out of cell u 1. through vesicles & vacuoles endocytosis § § 2. Honors Biology pinocytosis = “cellular drinking” phagocytosis = “cellular eating” exocytosis

Endocytosis § The movement of a substance into a cell by a vesicle is called endocytosis. REMEMBER: Endo = In § There are two types of endocytosis: 1. Pinocytosis (liquids) 2. Phagocytosis (particles) Honors Biology REMEMBER: Pino = Drink

Endocytosis Honors Biology

Pinocytosis Honors Biology

Phagocytosis Honors Biology

Exocytosis § The movement of a substance by a vesicle to the outside of a cell is called exocytosis. u Used to export proteins that are modified by the Golgi apparatus. Honors Biology REMEMBER: Exo = Exit!

Exocytosis Honors Biology

Exocytosis Honors Biology

Concept Map Special transport protein Honors Biology