1. There are 2 types of movement across the plasma membrane:
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Cellular Transport
There are various mechanisms that transport materials in and out of the cell. All of them involve the plasma membrane and are at the heart of homeostasis.
There are 2 types of movement across the plasma membrane:
PASSIVE Transport
and
ACTIVE Transport

2. Movement of particles across the cell membrane without using energy
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport
Movement of particles across the cell membrane without using energy
There are 3 types of passive transport:
Diffusion
Facilitated Diffusion
and
Osmosis

3. Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport – Cont’d
Type 1: Diffusion
Movement of substances across the cell membrane from and area of high concentration to an area of low concentration.
HIGH
LOW

4. Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport
Diffusion Cont’d
Having different concentrations in different areas creates a concentration gradient, and molecules will naturally move from high to low.
Students:
Draw arrows on the diagram to show which direction the particles will move.

5. More Diffusion Pics Passive Transport – Cont’d
7.4 – Cellular Transport
Passive Transport – Cont’d
More Diffusion Pics

6. The solute concentration is equal inside & outside the cell
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport
Diffusion – Cont’d
The solute concentration is equal inside & outside the cell
Dynamic Equilibrium
Molecules continue to move, but the overall concentration remains the same.

7. Type 2: Facilitated Diffusion
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport - Cont’d
Type 2: Facilitated Diffusion
Movement of materials across the plasma membrane through a protein
THIS DOES NOT REQUIRE ENERGY!

8. Diffusion of water across a selectively permeable membrane.
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport Cont’d
Type 3: Osmosis
Diffusion of water across a selectively permeable membrane.
Water will naturally move from where it is highly concentrated to where it is less concentrated.
This does NOT require energy!

9. Tonicity affects the movement of water
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport
Osmosis Cont’d
Tonicity affects the movement of water
Isotonic Solution – think “equal”
Hypotonic Solution – low solute concentration
Hypertonic Solution – high solute concentration

10. Chapter 7
Cellular Structure and Function

11. In an Isotonic Environment…
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport
Osmosis Cont’d
In an Isotonic Environment…
Water and dissolved substances diffuse into and out of the cell at an equal rate.
Plant Cell
Blood Cell
11,397x

12. In a Hypotonic Environment…
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport
Osmosis Cont’d
MEMORIZATION TIP: “Hypo-Hippo”
In a Hypotonic Environment…
Solute concentration is higher inside the cell.
Water diffuses into the cell.
Plant Cell
Blood Cell
13,000x

13. In a Hypertonic Environment…
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Passive Transport
Osmosis Cont’d
MEMORIZATION TIP: “Salt Sucks”
In a Hypertonic Environment…
Solute concentration is higher outside the cell.
Water diffuses out of the cell.
Plant Cell
Blood Cell
13,000x

14. A process that uses energy to move molecules across the cell membrane.
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Active Transport
A process that uses energy to move molecules across the cell membrane.
There are 3 types of active transport:
Active Transport using carrier proteins.
Endocytosis
Exocytosis

15. Active Transport with Carrier Proteins
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Active Transport
with Carrier Proteins
Uses energy to pump molecules across the cell membrane from a region of lower concentration to a region of higher concentration. This movement goes against the natural concentration gradient.

16. Use your prior knowledge: What is ATPase??
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Active Transport Cont’d
The Na+/K+ ATPase Pump
Moves three sodium ions out of the cell and two potassium ions into the cell
Use your prior knowledge: What is ATPase??

17. Active Transport Cont’d Endocytosis
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Active Transport Cont’d
Endocytosis
Process by which the cell uses energy to surround large particles and bring them into the cell

18. Active Transport Cont’d Exocytosis
Chapter 7
Cellular Structure and Function
7.4 Cellular Transport
Active Transport Cont’d
Exocytosis
Secretion of a large amount of material out of the plasma membrane