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32 Cards in this Set
- Front
- Back
Cell membrane structure: early theory
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Proteins were sandwiched between 2 layers of phospholipid molecules
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Cell membrane: problem
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Since the phospholipid tails are hydrophobic (hate water) this theory did not explain how water can travel freely through membranes
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Fluid mosaic model: accepted theory
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There is a double layer of phospholipids but the proteins are scattered through the membrane (mosaic). The proteins float among the semi-fluid phospholipids (fluids)
- the proteins have polar and non polar regions which accounts for their placement among the phospholipid bilayer |
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Carbohydrate chains
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Protein + carbohydrates = glycoprotein
Phospholipid + carbohydrate chain = glycolipid They function as cell identification markers. A body will attack cells with the wrong markers Example: organ rejections in transplants |
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Impermeable
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Nothing passes through
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Permeable
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Most things pass through
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Semi permeable
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Smaller molecules pass through but not large ones
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Selectively permeable
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Only certain molecules can pass through
Cell membranes are selectively permeable ( also called differentially permeable) |
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Diffusion
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Movement of a solute from an area of high concentration to an area of low concentration until evenly distributed. No membrane carrier, or ATP required
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Solute
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Made up of solid partials or molecules suspended in air or liquid
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Osmosis
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A special type of diffusion in which water moves from an area of low concentration across a membrane. No carrier or energy in the form of ATP are required
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Hypertonic solutions
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Solution with the greatest amount of solute compared to another solution
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Hypotonic solutions
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Solution with the least amount compared to another
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Isotonic solutions
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Two solutions with equal concentrations of solute to solvent
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Tonicity
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Refers to the concentration of a solute on a solution
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Facilitated transport
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Passive transport
- solute move across a membrane from and area of (high solute) to an area of (low solute) with the help of a carrier molecule. (Protein) no energy in the form of ATP is required Example: glucose |
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Active transport
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Solutes move from and area of (low solute) to an area of (high solute) across a membrane with the aid of a protein carrier molecule and ATP
Example of solute: lons such as Na+ |
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Movement of the medium
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Water or air currents speed up diffusion
Ex. Stirring cream and coffee |
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Movement of the medium
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Water or air currents speed up diffusion
Ex. Stirring cream and coffee |
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Endocytosis
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Process in which large materials enter a cell
Phagocytosis Pinocytosis |
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Movement of the medium
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Water or air currents speed up diffusion
Ex. Stirring cream and coffee |
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Endocytosis
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Process in which large materials enter a cell
Phagocytosis Pinocytosis |
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Phagocytosis
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A type of endocytosis in which whole cells, or bacteria, or cell fragments are taken in
Cell eating - very large pieces |
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Movement of the medium
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Water or air currents speed up diffusion
Ex. Stirring cream and coffee |
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Endocytosis
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Process in which large materials enter a cell
Phagocytosis Pinocytosis |
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Phagocytosis
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A type of endocytosis in which whole cells, or bacteria, or cell fragments are taken in
Cell eating - very large pieces |
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Pinocytosis
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A type of endocytosis in which molecules such as a proteins are taken in (liquid)
Cell drinking - smaller larger pieces |
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Movement of the medium
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Water or air currents speed up diffusion
Ex. Stirring cream and coffee |
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Endocytosis
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Process in which large materials enter a cell
Phagocytosis Pinocytosis |
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Phagocytosis
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A type of endocytosis in which whole cells, or bacteria, or cell fragments are taken in
Cell eating - very large pieces |
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Pinocytosis
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A type of endocytosis in which molecules such as a proteins are taken in (liquid)
Cell drinking - smaller larger pieces |
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Exocytosis
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A process by which products or wastes exit a cell. Reverse of endocytosis
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