Unit 2 objectives

Unit 2 objectives - Unit 2 Learning objectives Chapter 7:...

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Unit 2 Learning objectives Chapter 7: Membrane Structure and Function You should be able to: 1. Describe the principle of diffusion utilizing the concept of concentration and electrochemical gradients. Diffusion is the tendency for a molecule to spread out in a solution. It will go from a high concentration to a low concentration. The amount of a solute present in a solution is the concentration. When the solution moves across the membrane it is called passive transport and does not use any energy. 2. Explain/recognize what is meant by ‘electrochemical gradient’. Forces that act on an ion either by a chemical force or electrical force. 3. Describe the characteristics of the cell membrane and how these characteristics determine its permeability properties. Be able to recognize the molecules that will and will not passively diffuse across a cell membrane without help from membrane proteins. Outer most part of membrane made up of hydrophobic phospholipid heads while the inner most part of the membrane is made up of hydrophobic tails of phospholipids. Non-polar molecules pass easily through the membrane like hydrocarbons, oxygen and carbon dioxide. The cell also regulates the concentrations of Sodium, Potassium, Calcium and Chlorine. 4. Define osmosis and use the following terms correctly in describing situations in which osmosis takes place: isotonic, hypertonic, hypotonic Osmosis is the movement of water molecules across the cell membrane. Isotonic- same amount of water entering and exiting across the cell membrane Hypotonic- a solution enters faster through the membrane than as it exits causing the cell to expand Hypertonic- a solution enters slower through the membrane with water leaving the cell faster causing it to shrivel. 5. Explain/recognize the general structure of transmembrane proteins and be able to list/recognize/explain the various functions of membrane proteins. Transmembrane is a ribbon structure (alpha helix) and inside of the hydrophobic part of the cell that allow other hydrophobic molecules to pass through cell membrane. A type of intergral protein Made up of non-polar amino acids 6. Explain/recognize the role of cholesterol in a cell membrane Wedged between the phospholipids in animal cells Retrains the movement of phospholipids movement at room temperature Stops close packing of phospholipids Lowers the temperature for membranes to solidify at cold temperatures 7. Distinguish between simple diffusion and facilitated diffusion Facilitated diffusion- transport proteins allow polar molecules and ions to pass through the membrane 1. Needs Energy or ATP 2. Needs a pathway or protein to allow molecules to pass 3. Goes against electrical gradient Simple diffusion- doesn’t need any proteins or ATP to help molecules pass
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1. Goes with the electrical gradient 8. Define active transport and describe explain/recognize how cotransport and electrogenic pumps work Active transport- energy used to allow a solute cross the cell membrane
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Unit 2 objectives - Unit 2 Learning objectives Chapter 7:...

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