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Membrane Structure and Function - Coggle Diagram
Membrane Structure and Function
Membrane Structure
Fluid Mosaic Model
Phospholipid bilayer
Amphipathic (hydrophilic + hydrophobic regions)
Proteins embedded like mosaic
fluidity
Unsaturated = more fluid
Saturated = less fluid
Cholesterol regulates fluidity
Temp affects fluidity
Adaptation: winter wheat, cold fish
Membrane protiens
Types
Integral (transmembrane)
Peripheral
functions
Transport
Enzymatic activity
Signal transduction
Cell-cell recognition
Intercellular joining
Attach to cytoskeleton or ECM
Ex: HIV
membrane carbohydrates
Cell-cell recognition
Glycoproteins = protein + carb
Glycolipids = lipid + carb
Asymmetry: inside ≠ outside
Transport Across Membrane
Selective permeability
Hydrophobic pass freely
Hydrophilic need transport proteins
Passive Transport
Diffusion (no energy)
Osmosis (water)
Tonicity
Isotonic = balanced
Hypertonic = water leaves cell
Hypotonic = water enters cell
Facilitated diffusion
Channel proteins
Carrier proteins
Active Transport (needs ATP)
Sodium-potassium pump (animal cells)
Proton pump (plants, fungi, bacteria)
Cotransport
glucose
sucrose
Bulk Transport
Exocytosis
Example: insulin release
Endocytosis
Phagocytosis = eating
Pinocytosis = drinking
Receptor-mediated
Example: LDL cholesterol