Cell Membrane: Just Passing Through
Use the animation found at the link below to answer the following questions.
http://www.pbslearningmedia.org/asset/tdc02_int_membraneweb/
1. Describe how each of the following molecules will be transported across the cell
membrane.
Method of Transport Name of Protein Involved Does the process
(if applicable)
require energy?
Oxygen
Carbon
Dioxide
Glucose
Potassium
Sodium
Water
Enzyme
2. Explain why glucose continues to enter a cell, even when the concentration inside the
cell might be higher than outside.
3. How many ions can move through a protein channel per second (on average)?
4. Do protein channels have specificity? (i.e. Are they specific about what they let cross the
membrane or can any molecule go through any channel?)
5. Explain how the sodium/potassium pump works. Why does this process require ATP?
6. Correctly color code and identify the name for each part of the cell membrane.
Letter
Name/Color
Letter
Name/Color
Phospholipid bilayer (no color)
Receptor protein (red)
Protein channel (pink)
Cholesterol (blue)
Fatty acid tails (orange)
Glycoprotein (green)
Phosphate heads (yellow)
Carbohydrate markers (purple)
Match the cell membrane function with the correct letter from the cell membrane diagram.
Letter
Function
Letter
Function
Attracts water
Repels water
Helps maintain flexibility
Make up the bilayer
Involved in cell-to-cell
recognition
Help transport certain
materials across the membrane
7. Use arrows to show the direction of water movement into or out of each cell below.
8.
Label the tonicity for each solution below (isotonic, hypotonic, or hypertonic):
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