1. The Cell in It’s Environment
Chapter 3
Section 2
The Cell in It’s Environment
This section tells how things move into and out of cells.

2. Introduction
The cell membrane is selectively-permeable, which means some substances can pass through it while others cannot.

3. DIFFUSION Three ways substances can move into and out of a cell:
Osmosis
Active transport

4. DIFFUSION
In diffusion, molecules move from an area of HIGH concentration to an area of LOW concentration

5. DIFFUSION

6. DIFFUSION

7. OSMOSIS
In osmosis, water molecules diffuse through a selectively permeable membrane.

8. ACTIVE TRANSPORT
Two ways of moving things into and out of a cell that do NOT need energy are:
Diffusion
And
Osmosis
Moving materials across a cell membrane without using energy is called passive transport
High Normal Low
Outside Outside

9. ACTVE TRANSPORT
Active transport moves materials from low to high and requires cell’s energy
Passive transport moves material from high to low and does not require cell’s energy

10. ACTIVE TRANSPORT Two ways a cell move things through active transport
(Transport protein)
Engulfing
Food Particle

11. ACTIVE TRANSPORT & PASSIVE TRANSPORT
High
Active
Transport
Passive
Transport
No energy needed
ATP Energy needed
Low

12. ACTIVE TRANSPORT & PASSIVE TRANSPORT
Is the following sentence true or false?
As a cell gets larger, it takes longer for a molecule that has entered the cell to reach the middle of the cell.
TRUE