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?

______

______

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?

______

11.  List the four types of proteins found in a cell membrane.

______

______

12.  What is the purpose of cell transport & what is the difference between active transport and passive transport?

______

13.  What is equilibrium?

______

14.  What is diffusion? Why is diffusion an example of passive transport?

15.  What is osmosis, and why is it important in cells?

______

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.

______

In the space provided, write the letter of the description that best matches each term.

____ 20. concentration gradient
____ 21. equilibrium
____ 22. diffusion
____ 23. osmosis
____ 24. phospholipid
____ 25. carrier protein
____ 26. receptor protein
____ 27. lipid bilayer
____ 28. sodium-potassium pump
____ 29. water moves into the cell
____ 30. a state of ongoing equilibrium occurs
____ 31. water moves out of the cell / a.  the movement of a substance from a region where its concentration is higher to a region where its concentration is lower
b.  transports specific substances across a cell membrane
c.  binds to a signal molecule, enabling the cell to respond to the signal molecule
d.  The solution a cell is in is isotonic, meaning that it has the same solute concentration as the cytoplasm does
e.  made of a phosphate group and two fatty acids
f.  the state in which the distribution of a substance is even throughout a region
g.  The solution a cell is in is hypotonic, meaning that it has a lower solute concentration than the cytoplasm does.
h.  the difference in the concentration of a substance
i.  across a distance
j.  type of carrier protein that uses active transport to take sodium ions out of the cell and bring potassium ions into the cell
k.  a double layer of phospholipids that is the foundation of a biological membrane
l.  The solution a cell is in is hypertonic, meaning that it has a higher solute concentration than the cytoplasm does
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