Cell Transport PDF

Cellular Transport Objectives: Understand the difference between active and passive transport. Compare and construct Diffusion and Osmosis. Compare and construct the three types of Solutions.  Cell Transport Cells need to: – Take in things they need – Get rid o...

Cellular Transport Objectives: Understand the difference between active and passive transport. Compare and construct Diffusion and Osmosis. Compare and construct the three types of Solutions.  Cell Transport Cells need to: – Take in things they need – Get rid of the things they don’t need – Communicate with one another Two main types – Passive Transport – Active Transport  Passive Transport https://www.youtube.com/watch?v=_HBd7RXw880  Passive Transport The movement of materials across the cell membrane without using energy Caused by concentration gradient Works in both directions Three types: – Diffusion – Facilitated diffusion – Osmosis  Diffusion The process by which molecules spread from areas of high concentration, to areas of low concentration (Moving across the concentration gradient) No energy is required When the molecules are in continuous movement but no overall change it is called Dynamic EQUILIBRIUM Diffusion across a membrane Permeable – membrane through which molecules can pass Move from high concentrations to low until equilibrium is reached Small, uncharged particles (oxygen, carbon dioxide, most lipids) No energy required  Facilitated Diffusion Molecules that cannot directly diffuse across the membrane pass through special protein channels. NO ADDITIONAL ENERGY NEEDED  Facilitated Diffusion Uses Protein channels to move Ions & large molecules in and out the cell. Another type of transport protein, called carrier protein. Carriar protein change the shape of diffusion process to move the particles through the membrane.  Osmosis (Diffusion of water) Osmosis is the diffusion of water through a selectively permeable membrane down its concentration gradient From an area of high water concentration to an area of lower water concentration  How Osmosis works  A substance is solute dissolved in solvent.  Water is the solvent in the cell.  Concentration increase when the amount of solvent decrease.  Osmotic Solutions Isotonic concentrations of solute and solvent are equal. Hypertonic- higher concentration of solutes. Hypotonic- lower concentration of solutes  Active Transport https://www.youtube.com/watch?v=960jBAd-85k  Active Transport Movement against a concentration gradient Requires Energy (ATP) Allows for stockpiling One direction Types: – Molecular Transport (Protein Pumps) – Bulk Transport (Endocytosis and Exocytosis)  Active Transport Uses specialized transport proteins and protein pumps  Sodium- Potassium ATPase Pump Protein pumps Use the ATP energy to move ions or large molecules across the plasma membrane. Molecules are moved against their concentration gradient. Importance of Sodium and Potassium ions Consuming too little potassium and too much sodium can raise your blood pressure  Sodium- Potassium ATPase Pump The sodium–potassium pump is an enzyme found in the membrane of all animal cells For every ATP molecule that the pump uses, three sodium ions are exported and two potassium ions are imported  Transport of Large Particles Some substances are too large to move through the plasma membrane by diffusion or transport proteins and must get inside the cell by different Process. 1- Endocytosis how materials ENTER the cell 2- Exocytosis how materials EXIT the cell  Endocytosis The process by which cells absorb material (molecules such as proteins) from outside the cell by engulfing (swallow) it with their cell membrane  Exocytosis A cellular process where cells eject waste products or chemical transmitters (such as hormones) from the interior of the cell. Exocytosis is similar in function to Endocytosis but works in the opposite direction.