Warm up
• The cell membrane is called phospholipid bilayer.– What is a phospholipid?– Which part of the phospholipid is hydrophobic?– Which part of the phospholipid is hydrophilic?– Define the term semi-permeable.
– Quiz in 5 min.
Notes: Passive TransportCh. 5 Pg 97-102
Cell Transport• Molecules cross
membrane in several ways– Some methods of
transport require energy and some do not.
– Depends molecules size, polarity, and concentration inside versus outside.
Cell Transport
• Small molecules and larger hydrophobic molecules move through bilayer easily.– e.g. O2, CO2, H2O
Cell Transport
• Ions, hydrophilic molecules, and large molecules do not move through the membrane on their own. – e.g. Na+, K+
Passive Transport
• Movement across the membrane WITHOUT the use of energy
Concentration Gradient
• Molecules have kinetic energy
• Concentration Gradient: difference between high and low concentration• Molecules move “down”
gradient without energy• Equilibrium - when all molecules are evenly spread out
• Draw this!
Types of Passive Transport
1. Diffusion: Movement of molecules from high to low concentrations.
Types of Passive Transport
2. Facilitated Diffusion: Molecules too big to move across the membrane use carrier proteins • Ex. Glucose
Types of Passive Transport
3. Osmosis: diffusion of water across membrane
• Water moves where there are more solutes.
• Solute: What gets dissolved.• Solvent: What the Solute
dissolves in.• Solution: The mixture of the
solute and the solvent.
Which way will the water move?
1. Hypotonic• More solutes inside the cell, water moves in • The cell swells
Types of Tonicity
Draw These
Animal Cell Plant Cell
Hypertonic
• More solutes outside the cell, water moves out the cell
• The cell shrinks
Animal Cell Plant Cell
Draw these!
Isotonic• Equal solutes inside and outside• Water moves in and out at the same rate• Cell stays the same
Animal Cell Plant CellDraw These!
http://www.youtube.com/watch?v=OYoaLzobQmk&index=2&list=PLexD8cl0p1-Z8r4WyQXQ6R6-Hg81nERSg