Cell Membrane Practice Questions
1. Label the following structure on the diagram below, and then describe their function in the table that follows.
Peripheral Protein
Glycoprotein
Hydrophilic head
Phospholipid bilayer
Glycolipid
Hydrophobic tail
Integral protein
Cholesterol
Structure
Function
Phospholipid Bilayer
Integral Protein
Glycoprotein/Glycolipid
Cholesterol
2. Explain why the cell membrane is referred to as a “fluid mosaic”
3. Explain why the cell membrane is said to be selectively permeable.
4. Molecules that have which two properties CANNOT pass directly through the phospholipid bilayer. Give 2
examples.
5. Molecules that have which two properties CAN pass directly through the phospholipid bilayer. Give 2 examples.
Passive Transport Practice Questions
1. _________________________ is the process where water and certain dissolved particles like CO2 and H20
pass through the cell membrane into and out of the cell.
2. _________________________ refers to the tendency of particles to disperse (spread out), from an area of high
concentration to an area of low concentration, in a liquid or in air.
3. In the diagram below, label which test tube must contain the red
blood cell in salt water and which one must contain the red blood cell
in distilled (purified) water.
___________
___________
_____________
+
4. In the diagram to the above right, water is leaving the cell. Explain why (Na is sodium, a sodium ion.)
.
6. The movement of water and certain dissolved molecules into and out of cells is considered
transport because no cell energy is used during the process.
7. Cell membranes are semi-permeable (also known as “selectively permeable.”) What does that mean?
8. If the following particle is able to pass through a plasma membrane through osmosis, write “O” beside it. If it can
only enter through a special protein channel, write “PC” beside it.
Oxygen (O2) _____
Carbon Dioxide (CO2)_____
Glucose (C6H12O6)_____
Sodium ion (Na+)_____
Water (H2O) _____
9. In this illustration, notice that in the right U-tube, the water level on the right side of the tube is higher than it was
when the experiment began. What is the best explanation for why the water rose in the right side of the U- tube?
a. the particles diffused from the left side of
the u-tube to the right side of the u-tube
start
after 20 seconds
b. the particles diffused from the right side
of the u-tube to the left side of the utube
c. water flowed to the area with the
greatest concentration of particles
d. water flowed to the area with the lowest
concentration of dissolved particles
semi-permeable membrane
10. _____ In the diagram below, what can we infer about the cell that appears in the third panel?
a. the concentration of dissolved particles outside the cell was greater than the concentration inside the cell.
b. the concentration of dissolved particles inside the cell was greater than the concentration outside the cell.
c. the concentration of dissolved particles inside the cell and outside the cell is the same
11a. What type of transport is taking place in the image below? __________________________________
11b. Is this a type of active or passive transport?
12. Why must these particles pass through a special channel protein rather than pass directly through the plasma
membrane itself?