1. CH 5: Cell Membranes
Practice Test
answers

2. The movement of a substance toward an area of lower concentration is called ________.
diffusion
osmosis
active transport
exocytosis 1 2 3 4 5

3. Which component in the cell membrane restricts the passage of water-soluble substances?
glycolipids
protein
oligosaccharides
phospholipid 1 2 3 4 5

4. A membrane protein with two hydrophilic domains will generally:
be an enzyme
be an integral membrane protein
be a peripheral membrane protein
be involved with cell recognition 1 2 3 4 5

5. Which type of membrane protein will bind to a signal molecule such as a hormone?
adhesion
passive transporter
cell-to-cell communication
receptor 1 2 3 4 5

6. Communication proteins permit ________.
a cell to respond to extracellular signals
cells to import signal molecules from the extracellular environment
signaling between adjacent cells
body cells to distinguish foreign cells 1 2 3 4 5

7. Which combination of conditions would promote the most rapid diffusion across a cell membrane?
large molecule, high temperature, large concentration gradient
large molecule, low temperature, small concentration gradient
small molecule, low temperature, small concentration gradient
small molecule, high temperature, large concentration gradient 1 2 3 4 5

8. The term "selective permeability" describes the characteristic of membranes that ________.
restrict the passage of polar molecules
provide an anchoring between adjacent cells
allow membrane proteins to float freely within the membrane
permit some molecules to cross the membrane while preventing others from crossing 1 2 3 4 5

9. In the absence of a specific carrier protein, which type of molecule would be least likely to cross the membrane?
one that is large and polar
one that is small and nonpolar
one that is large and nonpolar
one that is small and polar 1 2 3 4 5

10. Why is diffusion the method by which O2 and CO2 are transported across the cell membrane?
it is faster than active transport
it allows ions and molecules to accumulate at higher concentrations within the cell than in the surrounding environment
the phospholipid bilayer is permeable to small, non-polar molecules
protein components are needed in the cell membrane for diffusion to occur 1 2 3 4 5

11. facilitated diffusion
Nerve cells contain an unusually high concentration of potassium; how are they able to obtain concentrations of potassium greater than those of the surrounding extracellular environment?
reverse diffusion
reverse osmosis
active transport
facilitated diffusion 1 2 3 4 5

12. Which of the following is a characteristic of active transport?
solute movement across the membrane is toward the side with the higher concentration
specific membrane proteins are required but no energy is needed
only molecules with potential energy greater than ATP are transported
it is a passive process 1 2 3 4 5

13. carriers for polar molecules insulation receptors enzymes
Proteins in membranes can provide all of the following functions except ________.
carriers for polar molecules
insulation
receptors
enzymes 1 2 3 4 5

14. swell as it gains water osmotically
Imagine cells suspended in a fluid to which a large amount of salt is suddenly added. If the cell membrane were impermeable to the salt, the cell would subsequently ________.
die
swell as it gains water osmotically
shrink as it loses water osmotically
experience no changes; since it's impermeable, salt has no effect 1 2 3 4 5

15. Osmosis can be described as ________.
movement of water from a region of high solute concentration to a region of low solute concentration
movement of solute from an area of low solute concentration to an area of high solute concentration
water molecules colliding with one another and the wall of a container
movement of water across a membrane from an area of low solute concentration to an area of high solute concentration 1 2 3 4 5

16. Which graphic, A, B, or C, portrays what would happen to cells in a hypertonic environment?1. B 2. C 3. A B C 1 2 3

17. The cell membrane ________.
is selectively permeable
has a bilayered phospholipid-protein structure
defines the boundary of the cell
all of the choices 1 2 3 4 5

18. The most abundant lipid in a cell membrane is ________.
phospholipid
steroids
cholesterol
triglycerides 1 2 3 4 5

19. Lose water from its vacuole. Not be affected
When a plant cell is placed in a hypotonic solution the plant cell will
Lose water from its vacuole.
Not be affected
Take in water and potentially burst
Take in water and expand up to its cell wall. 1 2 3 4 5

20. What feature of a vesicle would indicate an endocytotic formation?
there would not be any receptor proteins
it would contain cytoplasmic fluid
it would contain extracellular fluid
integral proteins would be absent 1 2 3 4 5

21. Phagocytosis is one type of ________.
active transport
osmosis
exocytosis
endocytosis 1 2 3 4 5