NAME:_________________________________ PERIOD:_____________






A. Cell Membrane

Color (or trace) and label figure 3.1:                       Label only:

1. phospholipids                                                          6. channel protein

            1a. phosphate-yellow                                      7. enzyme

            1b. fatty acid-blue                                           8. carrier protein

2. cholesterol- green                                                    9. marker protein        

3a. integral (embedded) protein-purple                      10. receptor protein

3b. peripheral (outside) protein-orange

4. carbohydrate-red









1. The primary membrane components are _________________and ________________.


2. Phospholipids contain polar ___________________ and nonpolar ________________.


3. Proteins embedded in the cell membrane are primarily ___________ (polar, nonpolar).


4. Proteins located on the outside of the cell membrane are primarily ________________

(polar, nonpolar).

5. The outside of the membrane is usually ________________(positive (+), negative (-)).


6. What membrane components (phospholipids, cholesterol, proteins, or carbohydrates) serve the following functions:

a. stabilize the membrane: __________________________________________________


b. transport water soluble (polar) substances: ___________________________________


c. allow movement of nonpolar substances across membrane: ______________________


d. act as receptors: ________________________________________________________


e. aid in cell recognition: ___________________________________________________


7. The diagram at the right represents a phospholipids molecule.

    1. Label the Phosphate Head and the Fatty Acid Tails of the molecule.


    1. The following are characteristics of either the Head or Tail of a

phospholipids molecule.  If the characteristic is true of the head,

place an H in the blank provided.  If it is true of the tail, place a T

in the blank.


_______hydrophobic                           ______ hydrophilic


_______consists of fatty acids           ______consists of phosphate


  1. Define each of the following terms:


  1. Hydrophobic:_____________________________________________________


  1. Hydrophilic: ______________________________________________________


  1. Where are the carbohydrates located? (inside of the cell or outside of the cell).
  1. Explain the importance of the location of the carbohydrates as related to their function.




  1. The fluid mosaic model is the current model describing the structure of the cell membrane.  To what does “fluid portion of the model refer? To what does the “mosaic” portion refer?


Fluid Portion

Mosaic Portion