Download Unit 3 Cellular Biology Chp 7 Membrane Module

CHAPTER 7
MEMBRANE STRUCTURE AND FUNCTION
Below is a diagram of a “cell membrane”.
1. Why is the cell membrane called a
“bilayer”?
2. In which group of macromolecules do the
molecules that make the bilayer belong?
3. What is the function of the cell membrane?
Below is a diagram of a section of cell membrane enlarging the phospholipids.
4. What do the terms “hydrophilic” and “hydrophobic” mean?
5. Why is the hydrophilic portion of each phospholipid molecule
oriented toward the extracellular fluid (outside the cell) or the
cytoplasm (inside the cell)?
Below is a diagram showing the addition of a dye (food coloring) to a beaker of water.
6. What process is this demonstration depicting?
7. Using the term “concentration”, explain what takes place
with the dye molecules.
Below is a diagram showing the process of “simple diffusion” across a “selectively permeable
membrane”.
8. Show the concentration gradient by labeling the side of the
cell with the highest concentration (use a + sign) and the side
with the lowest concentration (use a – sign) of solute.
9. Let’s say that the blue dots represent sugar molecules. If the
extracellular concentration of sugar was 6g/L in the beginning,
what could the intracellular concentration be in the beginning?
10. Using the same concentration of solute, what would the final
solute concentration be on both the outside and inside of the
cell?
Below is a diagram representing “osmosis” through a cell membrane. The green dots are solute
molecules and the blue/ white molecules are water.
A
B
11. Which side of the membrane (A or B) has the highest water
concentration?
12. Draw an arrow showing the direction water would move.
13. How many water molecules would be on each side when the
system has reached equilibrium?
Below is another diagram representing osmosis.
14. You will notice that the water column
rose on the left side and dropped on the
right side of the beaker. Explain this
phenomenon.
Below is a diagram showing the process of osmosis in two different cell types. The arrows represent the
movement of water.
1
2
3
15. Which cells are plant cells (top or bottom)? How
do you know?
+
16. Represent the water concentration gradient of
each cell (all 6) using a + sign for high, a – sign for
low, and an = sign for equal (see set #3 top cell).
16. Label the 3 different sets of cells with the
following appropriate term: Isotonic, Hypertonic,
and Hypotonic.
17. What would happen to a red blood cell if it was
placed in pure water (no solute)?
Below is a diagram representing 3 forms of cellular transport.
18. What types of molecules have to move by “facilitated”
diffusion?
19. What are the purple objects imbedded in the cell
membrane of this diagram?
20. What is the difference between “passive” and “active”
transport?
21. What is the purpose of “ATP” in this diagram?
Below are diagrams representing “endocytosis” and “exocytosis”.
22. What is the function of endocytosis?
23. What is the difference between the two
types of endocytosis?
24. Why might a cell use exocytosis instead of
facilitated transport?
Below is a diagram showing both unicellular and multicellular organisms.
25. One advantage of being multicellular is “cellular
specialization”. What does this term mean and how is it
an advantage over being unicellular?
Below are two diagrams representing levels of “cellular organization”. Be familiar with this concept.