Using Key Terms
1.When the concentration of a substance is the
same throughout a space, the substance is
a.in equilibrium.
b.a hypertonic solution.
c.undergoing passive transport.
d.undergoing active transport.
2.If a cell swells when placed in a solution,
the solution is
a.hypertonic. c.isotonic.
b.hypotonic. d.saturated.
3.Which of the following processes allows the
cell to dispose of wastes?
a.endocytosis
b.exocytosis
c.facilitated diffusion
d.sodium-potassium pump
4.The diffusion of water through a selectively
permeable membrane is called
a.osmosis. c.exocytosis.
b.endocytosis. d.active transport.
5.Identify each pair of terms, and explain the
difference in their meanings.
a.diffusion, equilibrium
b.receptor protein, carrier protein
c.endocytosis, exocytosis
d.active transport, passive transportUnderstanding Key Ideas
6.In diffusion, a substance moves
a.against its concentration gradient.
b.from an area of lower concentration to
an area of higher concentration.
c.independent of its concentration.
d.down its concentration gradient.
7.Substances enter or leave a cell
through the
a.cytoplasm. c.nucleus.
b.Golgi apparatus. d.cell membrane.
8.Facilitated diffusion
a.is driven by energy from ATP.
b.is a type of active transport.
c.employs receptor proteins.
d.employs carrier proteins.9.The sodium-potassium pump moves
a.sodium ions into the cell and potassium
ions out of the cell.
b.sodium ions out of the cell and
potassium ions into the cell.
c.sodium and potassium into the cell.
d.sodium and potassium out of the cell.
10.The binding of a signal molecule by a
receptor protein can
a.activate a second messenger inside the
receiving cell.
b.trigger enzyme activity in the cell.
c.change the permeability of the cell.
d.All of the above
11.The drawing below shows a plant cell that
has become shriveled after having been
placed in a solution. Is the solution most
likely hypertonic, hypotonic, or isotonic?
Explain your reasoning.12.Define the term homeostasis,and explain
how the sodium-potassium pump contrib-
utes to homeostasis in an animal.
13.When a cell takes in a food particle by
endocytosis, the vesicle that is formed may
fuse with a lysosome. How would that help
the cell digest the food particle?- Which types of cells does
HIV infect, and which of these does it
destroy? - Concept MappingMake a concept
map that shows how cells maintain homeo-
stasis. Include the following terms in your
map: concentration gradient, diffusion,
osmosis, and carrier protein.
Performance
ZONE
88 CHAPTER 4Review
CHAPTER REVIEW
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