1. The Cell Membrane The cell membrane has many functions:
________________
________________ ________________
A soap bubble is like a cell membrane.

2. A closer look at the cell membrane
The cell membrane is made of several types of _______________________.

4. Diffusion
Molecules move across the ___________ ___________by a process called diffusion.
Diffusion is the movement of molecules from areas of _____________ concentration to areas of _________________ concentration.

5. Diffusion
Molecules move into or out of the cell until there is an ____________ number on both sides of the cell membrane.

6. Diffusion
Water molecules are __________ enough to pass through the cell membrane by _________________.
__________________ is the diffusion of water across the cell membrane.

8. Other types of transport
Larger molecules like ____________, _____________ & _____________ sometimes diffuse through protein _______________.

9. Active transport
Active transport is a process that allows molecules to move across the cell membrane from ________________ to _______________ concentrations.
To do this requires _______________.

10. Other types of transport
A cell can take in large particles of food by “_____________” them.

11. Why are cells so small?
To understand why the volume of a cell increases faster than its surface area, let’s imagine a perfectly square cell.

12. Why are cells so small?
Which cell type has a higher volume to surface area ratio?