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CHAPTER 5: Membrane Structure, Synthesis, and Transport - Coggle Diagram
CHAPTER 5: Membrane Structure, Synthesis, and Transport
Membrane Structure
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The two leaflets (halves of bilayer) are asymmetrical, with different amounts of each component
Fluid-mosaic model
Membrane is considered a mosaic of lipid, protein, and carbohydrate molecules
Membrane resembles a fluid because lipids and proteins can move relative to each other within the membrane
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Cells maintain gradients
Transmembrane gradient - concentration of a solute is higher on one side of a membrane than the other
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Living cells maintain a relatively constant internal environment different from their external environment
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Osmosis
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If the solutes cannot move, water movement can make the cell shrink or swell as water leaves or enters the cell
In animal cells, it must maintain a balance between extracellular and intracellular solute concentrations to maintain their size and shape
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In plant cells, a cell wall prevents major change in cell size
Turgor pressure - pushes plasma membrane against cell wall, maintaining the shape and size
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In freshwater protists, like paramecium have to survive in a strongly hypotonic environment
To prevent osmotic lysis, contractile vacuoles take up water and discharge it outside the cell
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Transport Proteins
Are transmembrane proteins that provide a passageway for the movement of ions and hydrophilic molecules across membranes
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