November 19, 2015 Bell Work: What is a concentration gradient?
Objective: The student will be able to Distinguish between active and passive transport. Explain the function of a sodium-potassium pump andexplain its importance. Describe endocytosis and exocytosis. Today in History 1863 President Abraham Lincoln delivered theGettysburg Address as he dedicated a nationalcemetery at the site of the Civil War battlefield inPennsylvania. 1919 The Senate rejected the Treaty of Versailles. Attendance and Passes Cell Transport Active Transport Active Transport The transport of a substance across the cellmembrane against its concentration gradient. Requires the use of energy Supplied by ATP adenosine triphosphate Active Transport Can use carrier proteins, but transports substancesagainst their concentration gradient Called pumps Sodium Potassium Pump Found in animal cells
In a complete cycle, it transports three sodium ionsout of a cell and two potassium ions into a cell Na+ (sodium) K+ (potassium) Carrier protein Sodium Potassium Pump Sodium ions have a higher concentration outside ofthe cell Potassium ions have a higher concentration inside acell Actively transports both sodium and potassium Energy used to power the sodium potassium pump isATP Sodium-Potassium Pump
Three sodium ions inside the cell bind to the sodiumpotassium pump. A phosphate group is removed from ATPand also binds to the pump. The pump changes shape, transporting the 3 Na+ ions acrossthe cell membrane and releasing them outside the cell. Pump is exposed to the surface of the cell. 2 K+ ions outsidethe cell bind to the pump.The phosphate group is releasedcausing the carrier protein to change shape. The pump is exposed to the inside of the cell.The 2 K+ ionsare transported across the cell membrane and releasedinside the cell. Sodium Potassium Pump Movement in Vesicles Many substances are too large to be transported bycarrier proteins Proteins Polysaccharides Moved across the membrane in vesicles Endocytosis Movement of a substance into a cell by a vesicle
Cell membrane forms a pouch around a substance. Pouch closes and pinches off from the membraneto form a vesicle May fuse with lysosomes or other organelles. Endocytosis Exocystosis Movement of a substance from the inside of a cell tothe outside of a cell Vesicles fuse with the cell membrane, releasing theircontents. Use exocytosis to export proteins that are modifiedby the Golgi Apparatus Exocytosis Membrane Receptor Proteins
Proteins used to communicate with other cells in thebody Receptor Proteins A protein that binds to a specific signal molecule,enabling the cell to respond the signal molecule Most are embedded in the lipid bilayer of the cellmembrane The portion of the protein that fits the signal moleculefaces the outside of the cell Function of Receptor Proteins
Changes in permeability When coupled with an ion channel, the binding of a signalmolecule to the receptor protein causes the ion channel toopen. Important in the nervous system Function of Receptor Proteins Functions of Receptor Proteins
Second Messengers When activated, acts as a signal moleculein the cytoplasm Amplifies the signal of the first messenger Can change function of the cell by: Activating enzymes Triggering a series of biochemical reactions in a cell Change permeability by opening ion channels in the cell membrane. Function of Receptor Proteins Function of Receptor Proteins
Enzyme Action Act as an enzyme When a signal molecule binds to a receptor protein, it mayspeed up chemical reactions inside the cell Activate other enzymes Triggers other chemical reactions within a cell In Da Club- Membranes and Transport Vocabulary Worksheet Complete theWorksheet Cell Transport Worksheet
Complete thequestions using acompletesentence. Ticket Out What is active transport?