1. Section 4 Cellular Transport
Chapter 7
Section 4
Cellular Transport

2. MAIN Idea
Cellular transport moves substances within the cell and moves substances into and out of the cell.

3. Passive Transport
If particles move across the cell membrane WITH the concentration gradient
(from an area of High concentration to an area of Low concentration)
NO additional energy input is required

4. Three Modes of Passive Transport
Diffusion
Facilitated Diffusion
Osmosis

5. Diffusion
Movement of particles from an area of High concentration to an area of Low concentration
Three main factors affect the rate of diffusion:
Concentration
Temperature
Pressure
As concentration, temperature and pressure increase the rate of diffusion also increases.

6. Dynamic Equilibrium
Reached when diffusion of material into the cell is equal to diffusion of material out of the cell
Molecules continue to move, but the overall concentration remains the same.

7. Diffusion in a Cell

8. Facilitated Diffusion
Movement of materials across the plasma membrane using transport proteins
There are two types of transport proteins
Channel proteins open and close to allow substances to diffuse through the plasma membrane
Carrier proteins change shape to help move particles through

9. Osmosis
Diffusion of water across a selectively permeable membrane

10. Three Types of Solutions
Isotonic
Hypotonic
Hypertonic

11. Isotonic Solution
Solute concentration outside the cells is greater the inside the cell.
Water diffuses in and out of the cell at the same rate.
Cells keep their normal shape

12. Hypotonic Solution
Solute concentration outside of the cell is Less than the solute concentration on the inside the cell.
Water diffuses into the cell.
Cell shape is bloated or will burst

13. Hypertonic Solution
Solute concentration on the outside of the cell is higher (greater) than the solute concentration on the inside of the cell.
Water diffuses out of the cell.
Cell shape is shriveled up

14. Active Transport
Movement of particles AGAINST the concentration gradient (from an area of Lower concentration to an area of Higher concentration) across the cell membrane
Additional energy input is required

15. Types of Active Transport Pumps
Na+/K+ ATPase pump
Uses the energy of ATP to move three Na+ ions Out of the cell and two K+ ions Into the cell

16. Transport of Large Particles
Endocytosis
Process by which the cell surrounds and takes large particles Inside the cell

17. Transport of Large Particles
Exocytosis
Secretion of large particles Outside the cell (the reverse of endocytosis)