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Name: ______________________________
Team_____________________
EDUCATION IS FREEDOM!
Date__________/Mr. McIntire
Honors Biology
Cell Size and the Cell Membrane Wi(Re)
1. A newspaper ad for a local toy store indicates that a very inexpensive microscope available for a
small child is able to magnify specimens nearly as much as the much more costly microscope
available in your college lab. What is the primary reason for the price difference?
a. The ad agency is misrepresenting the ability of the toy microscope to magnify
b. The toy microscope does not have the same fine control for focus of the specimen
c. The toy microscope magnifies a good deal, but has low resolution and therefore poor quality
images
d. The college microscope produces greater contrast in the specimens
2. Which of the following is the best match between the research technique and its use?
a. Light microscopy: to see the structures of bacteria and viruses
b. Electron microscopy: to study the interaction between protists in a sample of pond water
c. Cell fractionation: to determine the metabolic functions of particular organelles
d. Freeze fracture: to determine the location of cytosolic enzymes
For each incorrect answer, record its CORRECT use and an advantage of this technique:
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3. The ultrastructure of a chloroplast could be seen with the best resolution using
a. Transmission electron microscopy
b. Scanning electron microscopy
c. Fluorescence microscopy
d. Light microscopy
4. All of the following statements regarding cell size are true EXCEPT?
a. Cells are small because their surface area is larger than their volume
b. As cells grow, their surface area increases
c. As cells grow, their surface area-to-volume ratio decreases
d. Large cells have a lower surface area-to-volume ratio
5. Who proposed that membranes are a phospholipid bilayer between two layers of hydrophilic
proteins?
a. H. Davson and J. Danielli
b. C. Overton
c. S. Singer and G. Nicholson
d. E. Gorter and F. Grendel
Is this the currently accepted model of the cell membrane? Explain why or why not.
6. Why are lipids and proteins free to move laterally in membranes?
a. The interior of the membrane is filled with liquid water
b. There are no covalent bonds between lipid and protein in the membrane
c. Hydrophilic portions of the lipids are in the interior of the membrane
d. There are only weak hydrophobic interactions in the interior of the membrane
7. An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely
be impaired in which function?
a. cell-cell recognition
b. maintaining fluidity of the phospholipid bilayer
c. attaching to the cytoskeleton
d. establishing the diffusion barrier to charged molecules
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8. When a membrane is freeze-fractured, the bilayer splits down the middle between the two layers of
phospholipids. In an electron micrograph of a freeze-fractured membrane, the bumps seen on the
fractured surface of the membrane are
a. Peripheral proteins
b. Phospholipids
c. Carbohydrates
d. Integral proteins
What other evidence supports the fluid mosaic model of the cell membrane?
9. Which of the following span the phospholipids bilayer, usually a number of times?
a. Transmembrane proteins
b. Integral proteins
c. Peripheral proteins
d. Glycolipids
What properties of proteins allows them to cross the membrane?
10. The fluidity of membranes in a plant in cold weather may be maintained by increasing the
a. Number of phospholipids with saturated hydrocarbon tails
b. Action of an H+ pump
c. Proportion of peripheral proteins
d. Number of phospholipids with unsaturated hydrocarbon tails
Explain your answer.
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What is another way that membrane fluidity could be maintained?
11. Which of the following is LEAST likely to be able to pass through the cell membrane?
a. O2
b. H2O
c. CO2
d. NaCl
Explain. What properties make it easy for a molecule to pass freely through the membrane?
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Questions 11-15: Match the letter from the labeled diagram below with its description.
12. _____ hydrophobic region of protein
13. _____ Phosphate head
14. _____ Glycolipid
15. _____ Fatty acid (hydrocarbon) tail
16. _____ Hydrophilic region of protein
17. _____ Phospholipid bilayer
18. _____ Glycoprotein
19. _____ Integral membrane protein
20. _____ Peripheral protein
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