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Passive and Active Transport Webquest
Part 1: Passive Transport Review
Go to
http://www.wiley.com/college/boyer/0470003790/animations/membrane_transp
ort/membrane_transport.htm and watch the video then answer the following
questions.
1. What are some examples of cellular transport?
2. What kinds of molecules have difficulty passing through a cell membrane?
3. What are some important parts of a cell membrane?
4. What kinds of molecules can easily pass through the cell membrane?
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5. Does water or solute pass through the membrane during diffusion?
6. Explain what happened to the concentrations of the solution inside and
outside the cell during diffusion.
7. What flows through the membrane during osmosis?
8. What happened to the balloons during osmosis?
9. Explains what happens during facilitated diffusion.
10. Do diffusion and osmosis occur at the same time?
11. Does this make equilibrium easier or harder to reach?
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Go to
http://www.glencoe.com/sites/common_assets/science/virtual_labs/LS03/LS03.ht
ml and pick one of the cells to put into the different solutions. Sketch the
concentration of the solution and the concentration in the cell and show the
direction of water movement.
Hypotonic
Hypertonic
Isotonic
Part 2: Active Transport
In active transport the cell needs to move ions and molecules against their
concentration gradient (low to high) in order to do this the cell needs to use energy
in the form of a molecule of ATP to move those ions. There are three main types of
active transport: endocytosis, exocytosis, and ion pumps. Use the following
websites to gather information on Active Transport.
Go to http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP11203 view the
animation and answer the following questions.
1. How much of the cell’s ATP will be used for active transport?
2. What is endocytosis?
3. What kinds of things enter the cell through endocytosis?
4. Why do they need to use endocytosis?
5. What is it called when the cell eats (bring in solid particles)?
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6. What is it called when the cell drinks (brings in fluid particles)?
7. What is exocytosis?
8. How does exocytosis work?
9. Being that the golgi apparatus usually processes proteins how do you think
proteins exit the cell?
Go to
http://programs.northlandcollege.edu/biology/biology1111/animations/transport
1.html click on active transport and watch the animation and answer the following
questions.
1. Why does active transport have to occur?
2. What are ion pumps?
3. What type of macromolecule are they?
4. How do ion pumps work?
5. Being that ion pumps are proteins do you think that they are selective when
it comes to the ions that they let across the membrane (much like enzymes
and substrates) or do you think they aren’t selective?
One important type of ion pump that is responsible for the transmission of nerve
signals is the sodium-potassium pump. Go to http://highered.mcgrawhill.com/sites/9834092339/student_view0/chapter44/sodiumpotassium_exchange_pump.html to learn more about this special ion pump.
1. What type of ions does the sodium potassium pump work with?
2. What are sodium potassium pumps responsible for in nerve cells?
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3. Watch what happens in the animation and explain how a sodium potassium
pump works.
Part 3: Analysis questions
1. Why doesn’t passive transport need energy and active transport does?
2. Why do you think cell walls are important in plants?
3. Before refrigeration people salted their food to keep it from spoiling. Why
did this work?
4. Carbon dioxide and Oxygen can move freely across the cell membrane. What
determines the direction of their movement?
5. In order for oxygen to enter our blood stream our body runs vessels full of
deoxygenated (no oxygen) blood across the alveoli (air sacs) that make up
our lungs. The oxygen then travels into the blood stream and then is sent
back to the heart and then throughout the body to our muscles that are
oxygen starved.
a. Why does the oxygen enter our blood stream?
b. What process does it use?
c. Why does the oxygen enter our muscles?
d. What process does it use?
6. Sometimes organisms need to maintain a concentration of an ion that is
much higher then their surrounding environment.
a. What process would the cell use to gain such a high concentration
gradient?
b. Explain the process that the cell would use to gain that concentration
gradient.
c. Why couldn’t diffusion be used?
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