Membrane & Transport Practice Terms & Concepts
Complete each statement by writing the correct term or phrase in the space provided.
1. What is homeostasis, and what are the 4 ways that the cell membrane helps maintain homeostasis?
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2. The ___________ ______________________ is made of a double layer of phospholipids. The
double layer of phospholipids is called a(n) ___________________ ______________________.
3. The lipid bilayer forms because there is ______________________ both inside and
______________________ of the cell.
4. The phosphate ______________________ of a phospholipid is polar. It is
______________________ ______________________ water.
5. The long fatty acid ______________________ of a phospholipid are nonpolar. They are
______________________ ______________________ water.
6. The lipid bilayer forms a barrier, preventing most molecules from passing through it. Only molecules that
are _______________ in size and ______________________ can pass through the lipid bilayer.
7. Ions, which are ______________________ particles, and ______________________ molecules
are repelled by the nonpolar interior of the lipid bilayer.
8. The cell membrane includes various kinds of ______________________. Some face the inside of the
cell. Some face the ______________________ of the cell. Others span the entire width of the
______________________ ______________________.
9. What are proteins made of? ________________________________________
10. Why do proteins stay within the lipid bilayer of the cell membrane?
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11. List the four types of proteins found in a cell membrane.
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12. What is the purpose of cell transport & what is the difference between active transport and passive
transport?
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13. What is equilibrium?
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14. What is diffusion? Why is diffusion an example of passive transport?
15. What is osmosis, and why is it important in cells?
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16. Explain how water moves across a cell membrane.
17. The transport of a substance across the cell membrane against its concentration gradient is called
______________________ ______________________.
18. The energy needed for active transport is usually supplied by _____________.
19. What is the sodium-potassium pump? Describe how it works.
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In the space provided, write the letter of the description that best matches each term.
____ 20. concentration
a. the movement of a substance from a region where its concentration is higher to a
gradient
region where its concentration is lower
____ 21. equilibrium
b. transports specific substances across a cell membrane
____ 22. diffusion
c. binds to a signal molecule, enabling the cell to respond to the signal molecule
____ 23. osmosis
d. The solution a cell is in is isotonic, meaning that it has the same solute
____ 24. phospholipid
concentration as the cytoplasm does
____ 25. carrier protein
e. made of a phosphate group and two fatty acids
____ 26. receptor protein
f. the state in which the distribution of a substance is even throughout a region
____ 27. lipid bilayer
g. The solution a cell is in is hypotonic, meaning that it has a lower solute
____ 28. sodiumconcentration than the cytoplasm does.
potassium pump
h. the difference in the concentration of a substance
____ 29. water moves
i. across a distance
into the cell
j. type of carrier protein that uses active transport to take sodium ions out of the cell
____ 30. a state of
and bring potassium ions into the cell
ongoing equilibrium
k. a double layer of phospholipids that is the foundation of a biological membrane
occurs
l. The solution a cell is in is hypertonic, meaning that it has a higher solute
____ 31. water moves
concentration than the cytoplasm does
out of the cell
m. the movement of water through a selectively permeable membrane from a more
dilute solution to a more concentrated solution
Transport Concept Mapping
Using the terms provided below, complete the concept map showing the characteristics of cell transport.
active transport
carrier proteins
channel proteins
osmosis
passive transport
pumps
simple diffusion
sodium-potassium pump
vesicles
concentration gradient
endocytosis