Transcript Cell Membrane Transport Notes

Cell
Membrane
Transport
Notes
Cell Membrane
• Definition: The semi-permeable outercovering of all cells.
• Composition:
– 2 Phospholipid Layers
– Protein Channels embedded
• Purpose / Function:
– Control traffic in and out of the cell
– Protection
Cell Wall
• Definition: The rigid outer-covering of plant,
and some bacterial cells.
• Composition:
– Cellulose (Plants)
– Chitin (Fungi)
– Peptidoglycan (Bacteria)
• Purpose / Function:
– Extra Support & Structure
– Extra Protection
Cell Membrane
Transport
• Methods:
– Diffusion (No energy needed)
– Osmosis (No energy needed)
– Active Transport (Energy needed)
• “Transport” = Things moving in and out of the
cell.
Concentration
• Definition: The amount of matter in a given
amount of space (area).
• High Concentration = More matter in a given
amount of space.
• Low Concentration = Less matter in a given
amount of space.
• “Concentration Gradient”: A difference in
concentrations.
Permeability
• Definition: The ability of matter to move
across a boundary.
• Cell Membranes are Semi-Permeable.
• “Semi-Permeable”: The ability of only certain
types of matter to move across a boundary.
Fully Permeable
Not Permeable
Semi- Permeable
Equilibrium
• Definition: State of balance.
• Matter moves in and out of cells to reach
equilibrium.
Diffusion
• Definition: The movement of particles across
a concentration gradient, from an area of higher
concentration, to an area of lower
concentration.
Osmosis
• Definition: The movement of water particles,
across a concentration gradient, from an area
of higher water concentration, to an area of
lower water concentration.
• *Water concentration with respect to Solute
concentration!
Solute & Solvent
• Solute: Solid particles
– Sugar
– Salt
• Solvent: Liquid which dissolves solute.
– Water