Transport Mechanisms of a Cell PDF

TRANSPOR T MECHANIS M OF Our Objectives: Explain the transport mechanisms of cell ( diffusion, osmosis, facilitated, and active transport) differentiate exocytosis and endocytosis  What is Diffusion? - the movement of substances from the region of their higher concentration to the reg...

TRANSPOR T MECHANIS M OF Our Objectives: Explain the transport mechanisms of cell ( diffusion, osmosis, facilitated, and active transport) differentiate exocytosis and endocytosis  What is Diffusion? - the movement of substances from the region of their higher concentration to the region of lower concentration. -the process in which particles spread out from each other -no cell energy required (passive)  Simple diffusion If bigger, charged polar molecules want to move in & out of the cell they need to use facilitated diffusion.  Facilitated diffusion Similar to simple diffusion but uses helper proteins found within the phospholipid bilayer to move solutes to & from the cell What is Osmosis? It is the diffusion of water across a semi- permeable membrane Terms we need to know: 1.) Hypertonic 2.) hypotonic 3.) Isotonic  1 Hypertonic the area with the higher solute concentration  2 Hypotonic the area with a lower solute concentration  3 Isotonic if two area have the same solute concentration  Active transport Substances are moved against their concentration gradient i.e, higher lower concentration to one of higher concentration. The transport protein uses energy from ATP to pump solute against its concentration gradient. Ex.: calcium pumps- moves calcium ions from across the cell membrane This process is important to maintain the concentration gradient of a particular solute at a certain level Calcium ions- act as potent messenger inside the cells and they affect the activity of many enzymes. Type of active transport: 1.) endocytosis 2.) exocytosis 3.) protein pumps Types of Endocytosis 1.)Phagocytosis -Phago means eat and Cytos (Kytos) means cell -is the process by which a cell uses its plasma membrane to engulf a large particle, giving rise to an internal compartment called the phagosome. 2.) Pinocytosis -is an active, energy consuming process where extracellular fluid and solutes are taken up into a cell via small vesicles.  Exocytosi s Is a process for moving large molecules out of the cell to the cell exterior.  Protein pump Protein pump is a type of membrane protein that requires energy to move molecules across the cellular membrane against a concentration gradient