Biology, Eighth Edition (Raven)

Chapter 5: Membranes

Pre Test

1
Why is the structure of the Singer and Nicholson membrane model called the "fluid mosaic model"? (p. 86)
A)The membrane exists at a liquid at regular body temperature, but has small regions of solidity to support it.
B)The phospholipids can move laterally within the plane of the membrane, and proteins are embedded within it to give it special functions.
C)Proteins provide flexibility within the rigid phospholipid bilayer.
D)It refers to the liquid lipid sheet which was "painted" with a stabilizing mosaic of protein on its outer and inner surfaces.
E)All of the above are valid reasons for the name of the model.
2
How can a membrane achieve more "fluidity"? (p. 90)
A)Changing the quantity of cholesterol within the fatty acid region.
B)Increasing temperature.
C)Introducing double bonds in the fatty acids.
D)Activating fatty acid desaturases.
E)All of the above can increase membrane fluidity.
3
Which of the following is (are) the major role(s) of proteins in a biological membrane? (p. 91)
A)Transporter of ions or large molecules.
B)Adhesion between adjacent cells.
C)Receptor for enzymes or other information at the cell's surface.
D)Attachment to the cytoskeleton.
E)All of the above are commonly found in biological membranes.
4
True or False: Water is unable to cross biological membranes. (p. 96)
A)True
B)False
5
How many ions can be transported across a membrane using the sodium-potassium pump and one ATP molecule under ideal conditions? (p. 98)
A)1
B)2
C)3
D)5
E)10
6
True or False: Receptor proteins allow for specific substrates to be taken in using a coated pit. (p. 100)
A)True
B)False
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