Membrane Transport Animations
Name
Using the following website to fill out and answer the questions on this worksheet.
http://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.html
The animation viewer is small so you may want to zoom in on the animation to better see what is going on. Pay
attention. The “back” button can only be used at the end of the animation segment. You may need to watch each
segment more than one time to answer the questions.
From the Main Menu, Click on Passive Transport.
Passive Transport
1. Passive transport is the movement of molecules across the cell that does not require an _______________________.
(What does expenditure mean?)
2. What are the three types of passive transport?
a. ________________________________________
b. ________________________________________
c. ________________________________________
Click “Next”
Cell Membrane
3. Fill in the blanks of the following two diagrams.
____________________
____________
__
____________
__________
Watch the rest of the animation, follow along carefully. If you read this, draw an arrow by your name.
4. Why is the cell membrane described as a lipid bilayer?
5. Why is it important to note that the lipid bilayer is fluid?
6. Label the diagram to the right:
a. Which part of the lipid bilayer is polar (hydrophilic — water liking)?
b. Which is non-polar (hydrophobic — water non-liking)?
7. Which type of molecules have difficulty passing through the membrane? Why
do you think so?
8. Which type of molecules pass easily through the membrane? Why do you think so?
Click Next or Click on “Simple”
Simple Diffusion
9. Diffusion is the movement of molecules from an area of ____________________________________ to an area of
___________________________________________.
10. The term ___________________________________________refers to the relative density of one chemical substance
versus another.
Click Next
11. The rate of diffusion is dependent on these four things:
a.
b.
c.
d.
12. Simple Diffusion ends when equilibrium is met.
a. What is meant by “equilibrium”?
b.
Since we are talking about living things, what is better / more accurate word choice to describe this condition
in living cells ___________________________________. (Check the Intro to Chapter 7.)
Click Next or Click on Facilitated
Facilitated Diffusion
13. Facilitated diffusion is the ___________________________ of molecules down a concentration gradient with the aid
of ________________________________________.
14. Does facilitated diffusion require the use of energy (ATP)? ________
15. List the characteristics of some molecules that make them need help getting across the cell membrane?
16. How does a protein “facilitate” the diffusion of the molecule?
17. Sketch two protein channels in a membrane showing facilitated diffusion (one showing before and one after).
Click Next or Click on Osmosis
Osmosis
18. Define the term Osmosis.
19. Compare and contrast Simple Diffusion and Osmosis. What is similar? What is different? Use a Venn Diagram.
20. Compare a hypertonic solution to a hypotonic solution. Draw a picture or two showing what is going on.
21. Water travels across a cell membrane… (Circle one)
a. from a hypotonic environment to a hypertonic environment
or
b. from a hypertonic environment to a hypotonic environment.
22. Explain why water molecules move across a cell membrane.
Click Next
Active Transport
22. ________________________________ is the pumping of molecules ______________their ____________________
with the expenditure of energy (ATP).
23. Why is active transport necessary?
24. Explain the difference between Passive and Active Transport.
25. Why do cells need to move molecules against the concentration gradient into the cells or out of the cells?
26. Describe the three different types of Active Transport used by cells to get molecules inside.
1.
2.
3.
27. What are the three different kinds of Endocytosis? Use the back of this page for more space & drawings.
a.
b.
c.