Name: _______________________
Guided Practice Questions – Cellular Transport
1. What is the difference between passive transport and active
transport?
a. Passive transport does not require energy (ATP) for molecules
to move across the membrane. Active transport requires energy
(ATP) to pump molecules across the membrane.
2. Why is diffusion considered a passive process?
a. Diffusion is a passive process because diffusion does not
require energy (ATP) for molecules to move.
3. What is the difference between “simple” diffusion and facilitated
diffusion?
a. Facilitated diffusion requires the use of a channel protein and a
membrane for molecules to move.
4. How is osmosis different from diffusion? How is it the same?
a. Osmosis is the diffusion of water through a semi-permeable
membrane, whereas diffusion is the dispersing of any molecule.
b. Osmosis and diffusion are both types of passive transports and
are both processes of describing molecules moving with the
concentration gradient.
5. What does it mean if a cell has reached dynamic equilibrium?
a. A cell has reached dynamic equilibrium when the water-solute
concentration is equal inside and outside of the cell.
6. What will happen to a cell if it is placed in a hypotonic solution?
a. In a hypotonic solution a cell will swell or burst.
7. What direction will the water in a cell go if the solute particles are
20% inside the cell and 20% outside the cell in the solution?
i. Water will move back and forth.
b. What is this type of solution called? – isotonic solution
Name: _______________________
8. Why do animal cells have contractile vacuoles?
a. Animal cells use contractile vacuoles to pump excess water out
of the cell to keep the cell from bursting.
9. How does an animal cell and a plant cell react differently to
plasmolysis.
a. During plasmolysis an animal cell will lose shape and shrink
and possibly die to due lack of water. During plasmolysis a
plant cell will dry up and die due to lack of water. (Plasmolysis is
the process in plant cells where the cytoplasm pulls away from the cell
wall due to the loss of water through osmosis)
10. What is turgor pressure and how does this benefit a plant cell?
a. Turgor pressure is the result of the cell membrane expanding
due to the high concentration of water inside the cell and
placing pressure on the cell wall. Turgor pressure gives the
plant cell its rigidity.
11. Give a non-science example of a cell using active transport.
a. Any example showing a pump to move or showing movement
against the flow of traffic/movement
Name: _______________________
Guiding Questions – Plasma Membrane Structure (chp 3)
1.
Why is the plasma membrane referred to as a fluid mosaic model?
a. Molecules are free to move side to side and the cell membrane
has different proteins embedded within the cell membrane.
2.
Explain the term “selectively permeable.” Use a non-science
example if necessary.
a. Selectively permeable (aka semi-permeable) means to some
molecules can pass and others cannot pass through the cell.
Non-science example  US Border Patrol
3.
What substances must be kept at constant concentrations in the cell?
a. Water, glucose, oxygen, carbon dioxide and waste
4.
What types of molecules can diffuse across the membrane?
Small, non-polar molecules
a. Give examples of three molecules that can diffuse directly.
Water, oxygen
5.
Describe the three types of transport proteins.
a. Transport proteins – help move molecules in/out of cell (like a
bus)
b. Receptor proteins – communicate info from cell to cell (like a
text)
c. Marker proteins – identify type of cell (like a name tag)
6.
What process essential to all living
things does the plasma membrane
control?’
a. Homeostasis – the process of
maintaining a stable
environment inside the cell as
the outside environment changes
7.
Label the cell membrane: