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Chapter 7 Membrane Structure and Function - Coggle Diagram
Chapter 7 Membrane Structure and Function
Types of Transport
Movement of substances across the cell membrane, either with or without energy.
Passive Transport (No ATP Required)
Diffusion: Movement from high to low concentration.
Works best for small, nonpolar, uncharged molecules
Facilitated Diffusion: Same as diffusion but uses transport proteins.
Osmosis: Diffusion of water across a semi-permeable membrane.
Water moves toward the higher solute concentration (low to high solute)
Active Transport (Requires ATP)
Molecules move from low to high concentration (against the gradient).
Endocytosis: Cell takes in substances.
Phagocytosis: "Cell eating" (solids)
Pinocytosis: "Cell drinking" (liquids)
Exocytosis: Cell expels substances.
Osmosis & Water Balance
Regulation of water movement and concentration within cells.
Tonicity
Measure of the effect of a solution on water movement.
Hypertonic: More solute outside → cell loses water
Hypotonic: More solute inside → cell gains water
Isotonic: Equal solute → no net water movement
Osmoregulation
Maintaining water and solute balance in cells.
Concentration Gradient
The difference in concentration across a space.
Temperature
Higher temperatures increase diffusion rate.
Membrane Structure & Fluidity
The composition of the membrane affects its function and movement.
Amphipathic Molecules
Have both hydrophilic and hydrophobic parts.
Example: Phospholipids
Fluidity of Membrane
Maintained by unsaturated fatty acids and cholesterol
Essential for proper membrane function and protein movement.
Membrane Potential
Voltage across the membrane due to ion differences.
Important for nerve signals and transport processes.
Membrane Proteins & Transport Mechanisms
Proteins embedded in the membrane that assist in molecule movement.
Transport Proteins
Move substances across membranes.
Channel Proteins: Create hydrophilic tunnels for ions or molecules.
Carrier Proteins: Bind and change shape to move substances.
Gated Channels
Open/close in response to stimuli.
Sodium-Potassium Pump
Uses ATP to pump
Na⁺ out of the cell, K⁺ into the cell
Proton Pump
Pumps H⁺ (hydrogen ions) out of the cell to build gradient.
Cotransport
Active transport of one molecule drives the transport of another.
Example: Sucrose-H⁺ cotransport (SGCT)