Download 2. Fill in: Phospholipids have their

BIO101
Membrane Worksheet
Name _____________________________________
1. Label: Lipid bilayer, phospholipid head, phospholipid tail, peripheral protein, channel protein, hydrophobic
portion, hydrophilic portion, an amphipathic protein, an integral protein.
2. Fill in: Phospholipids have their _____________ polar heads facing the intracellular and extracellular
fluid. The ___________________ tails face each other. Another type of lipid present in the plasma
membrane is _______________ which stabilizes membrane fluidity. The proteins found in the plasma
membrane may be ____________ proteins, which penetrate the membrane, or _____________ proteins,
which occur either on the cytoplasmic side or the outer surface side of the membrane.
3. Place an "X" next to any of the statements below that are true about the plasma membrane.
_____ The greater the concentration of unsaturated fatty acids, the more fluid the bilayer.
_____ Phospholipid molecules frequently flip-flop from one layer to the other.
_____ Most proteins can drift laterally in the fluid lipid bilayer.
_____ The carbohydrate portions of glycoproteins project internally.
_____ Cell membranes are fluid at body temperature (37oC)
4. Fill in the Table
Membrane structure/molecule
Cholesterol
Channel protein
Carrier protein
Receptor protein
Enzymatic protein
Glycoprotein
Aquaporin
Sodium/Potassium pump
Ligand
Function
BIO101
Membrane Worksheet
5. Label the figure below. Draw arrows to indicate each of the following processes: Diffusion, Na+/K
Transport pump, Facilitated diffusion, Osmosis
a.
b.
c.
d.
e.
f.
Name the process(es) in the figure that are active transport.
Name the transport process(es) that require a protein.
Which two items in the figure are charged ions?
Which two of the molecules in this figure enter the cell only (do not normally exit)?
Name the process in the figure that can operate against a concentration gradient
Which of the substances transported in the figure is the largest?
6. Place a check in the one appropriate column for each statement
STATEMENT
1. The concentration of dissolved substances in the solution is lower than the
concentration inside the cell.
2. When a cell is placed in this solution, water will enter the cell by osmosis
resulting in osmotic (turgor) pressure.
3. The concentration of dissolved substances (stuff) in the solution is the same
as the concentration inside the cell.
4. The concentration of dissolved substances (stuff) in the solution is higher
than the concentration inside the cell.
5. When this solution is injected into the body no cell disruption occurs because
no net osmosis occurs.
6. Putting plant in this solution will result in water loss and cause plant to wilt.
Isotonic
Hypotonic
Hypertonic
BIO101
Membrane Worksheet
7. Osmosis
At the beginning of an osmosis experiment, sides A and B contain aqueous solutions with the following solutes.
Side A: 1 M glucose, 0.1 M NaCl
Side B: 2 M glucose, 0.2 M NaCl
The volumes on either side of the apparatus are the same. A selectively permeable membrane separates the two
sides. The membrane is permeable to water and to NaCl but not to glucose.
The apparatus is allowed to stand for a number of days. The following questions refer to this experiment. For
each of these items, answer true or false:
1.
2.
3.
4.
5.
6.
7.
8.
___ The glucose on side B will become less concentrated than that on side A.
___ The NaCl solution will become more concentrated on side A and less so on side B
___Glucose does not move across the membrane
___ The concentration of NaCl on side A will eventually equal that on side B
___The passage of water through the membrane is an example of osmosis
___ The volume on side B will rise
___ There will be a net movement of water molecules from side B to side A
___The passage of sodium and chloride ions through the membrane in this case is an example of
osmosis
9. ___ There will be a net movement of water from the hypertonic to the hypotonic solution
BIO101
Membrane Worksheet
The apparatus is allowed to stand for a number of days. The following questions refer to this experiment. For
each of these items, select the most appropriate phrase from the key below:
A. Both the statement and the reason are true.
B. The statement is true, but the reason is false
C. The statement is false but the reason is an accepted fact or principle having no bearing upon the statement.
D. Both the statement and the reason are false
. ___1. The glucose on side B will become less concentrated and that on side A more concentrated because a
substance tends to diffuse from a less concentrated region to one of greater concentration.
___2. The NaCl solution will become more concentrated on side A and less so on side B because sodium ions
and chloride ions will pass through the membrane from a region of greater concentration to one of lesser
concentration.
___3. The glucose solution will become more concentrated on side B and less concentrated on side A because
the glucose will diffuse through the membrane from a region of greater concentration to one of lesser
concentration.
___4. Glucose does not move across the membrane because the solution on side A is isotonic with the solution
on side B.
___5. The glucose solution of side A will become less concentrated and that on side B more concentrated
because water will move by osmosis from side B to A, thus diluting side A.
___6. The concentration of NaCl on side A will eventually equal that on side B because
sodium and chloride ions will move by diffusion from one side to another until a uniform density is reached.
___7. There will be a net movement of water from side A to side B because
water will move from the hypertonic solution to the hypotonic solution when the two are separated by a
selectively permeable membrane.
___8. The passage of water through the membrane in this case is an example of osmosis because
osmosis is defined as the net movement of water through a selectively permeable membrane.
___9. The water level on side A will rise because the solution in side A had a higher osmotic concentration and
thus a higher osmotic pressure than the solution in side B.
___10. The passage of sodium and chloride ions through the membrane in this case is an example of osmosis
becausenosmosis is defined as the passage of any substance through a selectively permeable membrane from a
region of greater concentration to one of lesser concentration.
ANSWER KEY (DON’T PEEK!!!):
1-D, 2-A, 3-B, 4-B, 5-A, 6-A, 7-D, 8-A, 9-A, 10-D