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Chapter 7: Membrane Structure + Function - Coggle Diagram
Chapter 7: Membrane Structure + Function
Cellular Membranes are Fluid Mosaics
Fluidity of Membranes
Definition:
Membranes held together by weak hydrophobic interactions
Differences in Membrane Lipid Composition
Definition:
Lipid composition is adapted to environmental conditions in many organisms
Example
In fish that live in extreme cold, cell membranes have a higher proportion of unsaturated hydrocarbon tails
Fluid Mosaic Model
Definition: Protein molecules bobbing in a layer of phospholipids, looking like a mosaic
Membranes in Selective Permeability
Definition:
The exchange of materials between cells and their surroundings
Example
Phospholipids
Fatty acid tails
Saturated
Unsaturated
Amphipathic
Definition: Both hydrophobic and hydrophilic
Passive Transport
Definition:
The movement of small molecules across a cell membrane, requires no energy
Facilitated Diffusion
Definition: Passive movement of molecules across the plasma membrane
Ion channels
Definition: Facilitates the transport of ions
Gated channels
Definition: Opens or closes in response to stimulus
Active
Transport
Definition:
Uses energy to move substances against the concentration gradient
Sodium-Potassium Pump
Definition: Moves potassium into the cell and sodium out of the cell
Bulk Transport
Definition:
The movement of large molecules through a cell membrane
Example
Exocytosis
Definition: Transport vesicles fuses into the membrane and releases their contents into the cell
Endocytosis
Definition: Macromolecules are taken into the cell in vesicles
Phagocytosis
Definition: Cellular eating
Pinocytosis
Definition: Cellular drinking
Receptor-mediated endocytosis
Definition: Solute binds to receptors
Membrane Proteins and their Functions
Peripheral Proteins
Definition: Bound to the surface of the membrane
Integral Proteins
Definition: Penetrate the hydrophobic core
Transmembrane Proteins
Definition: Integral proteins that span the membrane
Transport Proteins
Carrier Protein
Definition: Binds to molecules and changes shape to allow them across the membrane
Channel Protein
Definition: Hydrophilic channel that certain molecules can use as a tunnel
Aquaporins
Definition: Increases the rate of passage of water molecules
Definition: Helps hydrophilic substances cross the membrane easily
Cell-Cell Recognition
Definition: Cells recognize each other by binding to molecules on the surface on the membrane
Glycolipids
Definition: Carbohydrates bonded to lipids
Glycoproteins
Definition: Carbohydrates bonded to proteins
Osmosis
Definition: The diffusion of water molecules across a selectively permeable membrane
Tonicity
Definition: The ability of a surrounding solution to cause a cell to gain or lose water
Isotonic
Definition: Equal solute concentration
Flaccid
Definition: The plant cell is limp and wilts
Hypertonic
Definition: The solute concentration is greater than the inside of the cell
Plasmolysis
Definition: The cell shrivels and pulls away from the cell wall
Hypotonic
Definition: The solute concentration is less than the inside of the cell
Turgid
Definition: The plant cell is firm