Date ________________________ pg. _____
The Cell Membrane and Cell Transport
Directions: Use the online resources to learn about the structure of the cell (or plasma) membrane
and how it aids in cell transport.
1. Visit Resource 1 - cK-12 Phospholipid Bilayers.
a. What is the function of the plasma membrane?
b. What does selective permeability mean?
c. Watch the plasma membrane clip linked in this section.
d. What is the plasma membrane mainly composed of?
e. What is meant by phospholipid bilayer?
f. What does hydrophilic mean?
g. What does hydrophobic mean?
h. Under the Explore More section, click the link Construction of a Cell Membrane
i. In addition to lipids, what else is the cell membrane made of?
ii. What substances can pass through the cell membrane without help?
iii. What substances must get help in order to pass through the cell membrane?
iv. Complete the 10 question review.
2. Visit Resource 2 – Phospholipids.
a. Scroll down to the third image. Sketch and label the phospholipid bilayer below:
3. Visit Resource 3 – How Diffusion Works.
a. Describe what happens to moving molecules within a solution.
b. In terms of molecules, explain what happens to a sugar cube when it is placed into a beaker
of water.
c. Define diffusion.
d. What can affect the rate of diffusion?
4. Visit Resource 4 – How Osmosis Works.
a. Most _________________________ molecules cannot freely cross the cell membrane. Is
this true for water molecules?
b. Define osmosis.
c. Why did the water molecules move from the left side to the right side? Use the word
concentration in your response.
d. The solution with (higher / lower) solutes is hypertonic.
e. The solution with (higher / lower) solutes is hypotonic.
5. Visit Resource 5 – Active and Passive Transport.
a. Why are active and passive transport important for a cell?
b. What is the main difference between active and passive transport?
c. Complete the table below:
Active Transport
Definition
Functions
Types of
Particles
Transported
Examples
Importance
Passive Transport