1. Things to Do Objective Pick up notes Go over test
Discuss passive transportation
Learn about diffusion

2. Passive Transport
Notes 1

3. Root Words Cyt- cell Endo- within Exo- Exit Hyper- above Hypo- below
Inter- between
Iso- equal
Mit- thread
Phag- to eat
Pino- to drink
Som- body
Poly- Many
Mono- One
Bi- Two
-Ose: Sugar
-Ase: Enzyme

4. Movement in and out of a cell
Plasma membrane is selectively permeable
Also called semipermeable
Permeable - The ease to which molecules can pass through a biological membrane
Controls what leaves and enters the cell
Some molecules can come and go freely while some require energy
Passive Mechanisms - no energy required
Diffusion
Facilitated Diffusion
Osmosis
Active Mechanisms - uses energy
Active Transport
Endocytosis
Exocytosis

5. Diffusion
Molecules or Ions move from higher concentration to lower concentration
This difference in concentration is called a concentration gradient
Even distribution is called equilibrium
Can only occur if two criteria are met:
Membrane is permeable to that substance
A concentration gradient exists
Example:
Carbon Dioxide is always high in cells because it is produced as a waste product
CO2 is low outside the cell because the body works to get rid of it
Diffusion of CO2 occurs regularly

6. Diffusion

7. Diffusion

8. What Can Cross the Membrane
Non-charged molecules
Oxygen (O2)
Carbon Dioxide (CO2)
Water (H2O)
Nitrogen (N2)
Larger or charged molecules can't pass through the membrane
This is called Facilitated Diffusion and does not require energy

9. Facilitated Diffusion
Used for molecules that can't pass through the membrane
Use protein channels and ion channels
Glucose and amino acids combine with special protein carrier molecules
Changes the shape of the carrier and allows them through
Glucose detaches on the inside
Protein carrier molecule returns to normal
Moves from high concentration to low concentration
Limited by the number of protein carrier molecules

10. Facilitated Diffusion

11. Passive Transport