AP Bio Ch. 7 Study Guide Test Your Knowledge
Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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If a single layer of phospholipids coats the water in a beaker, which parts of
the molecules face the air?
a. | the phosphate group | b. | the hydrocarbon tails | c. | both heads and tails
because the molecules are amphipathic and lie sideways | d. | the glycolipid regions | e. | No parts of the
molecules face the air, because the phospholipids dissolve in the water and do not form a
layer. |
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2.
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Support for the fluid mosaic model of membrane structure comes from
a. | freeze-fracture preperation and electron microscopy | b. | the movement of
proteins in hybrid cells | c. | the amphipathic nature of many membrane
proteins | d. | a and c | e. | a, b, and c |
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3.
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Glycoproteins and glycolipids are important for
a. | facilitated diffusion | b. | active transport | c. | cell-cell
recognition | d. | intercellular joining | e. | signal-transduction
pathways |
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4.
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Which of the following is the most probable description of an integral,
transmembrane protein?
a. | amphipathic with a hydrophilic head and a hydrophobic tail region | b. | a globular protein
with hydrophobic amino acids in the interior and hydrophilic amino acids arranged around the
outside | c. | a fibrous protein coated with hydrophobic fatty acids | d. | a glycolipid
attached to the portion of the protein facing the exterior of the cell and cytoskeletal elements
attached to the interior portion | e. | a middle region composed of alpha helical
stretches of hydrophobic amino acids, with hydrophilic regions at both ends of the
protein |
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5.
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A cell is manufacturing receptor proteins for cholesterol. How would those
proteins be oriented before they reach the plasma membrane?
a. | facing inside the ER lumen but outside | b. | facing inside the ER lumen and
inside | c. | attached outside the ER and outside | d. | attached outside the ER but
facing | e. | embedded in the hydrophobic center |
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6.
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The fluidity of membranes in a plant in cold weather may be maintained by
increasing the
a. | proportion of peripheral proteins | b. | action of a H+ pump | c. | concentration of
cholesterol in the membrane | d. | number of phospholipids with unsaturated
hydrocarbon tails | e. | number of phospholipids with saturated
hydrocarbon tails |
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7.
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Initially, the solution in side A, with respect to that in side B,
a. | has a lower solute concentration | b. | has a higher solute
concentration | c. | has an equal solute concentration | d. | is lower in the tube | e. | is higher in the
tube |
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8.
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During the period before equalibrium is reached, which molecule(s) will show net
movement through the membrane?
a. | water | b. | glucose | c. | sucrose | d. | water and sucrose | e. | water and
glucose |
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9.
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After the system reaches equalibrium, what changes can be observed?
a. | The water level is higher in side A than side B | b. | The water level is
higher in side B than side A | c. | The molarity of glucose is higher in side A
than in side B | d. | The molarity of sucrose has increased in side A | e. | Both A and C have
occured |
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10.
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An animal cell placed in a hypotonic environment will
a. | become flaccid | b. | become turgid | c. | burst
(lyse) | d. | plasmolyze | e. | shrivel |
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11.
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You observe plant cells under a microscope as they are placed in an unknown
solution. First the cells plasmolyze; after a minute, the plasmolysis reverses and the cells appear
normal. What would you conclude about the unknown solution?
a. | It is hypertonic to the plant cells, and its solute cannot cross the plant cell
membranes | b. | It is hypotonic to the plant cells, and its solute cannot cross the plant cell
membranes | c. | It is isotonic to the plant cells, but its solute can crossthe plant cell
membranes | d. | It is hypertonic to the plant cells, but its solutes can cross the plant cell
membranes | e. | It is hypotonic to the plant cells, but its solute can cross the plant cell
membranes |
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12.
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Which of the following is not true about osmosis?
a. | It is a passive process in cells without walls, but an active one in cells with
walls | b. | Water moves into a cell from a hypotonic environment | c. | Solute molecules
bind to water and decrease the free water available to move | d. | It can occur more
rapidly through channel proteins known as aquaporins | e. | There is no net osmosis when cells are in
isotonic solutions |
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13.
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Which of the following is not true of carrier molecules involved in facilitated
diffusion?
a. | They increase the speed of transport across a membrane | b. | They can concentrate
solute molecules on one side of the membrane | c. | They may have specific binding sites for the
molecules they transport | d. | They may undergo a change in shape upon binding
of solute | e. | They do not require an energy investment from the cell to
operate |
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14.
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Facilitated diffusion of ions across a cellular membrane requires ____________;
and the ions move _____________.
a. | energy and channel proteins; against their electrochemical
gradient | b. | energy and channel proteins; against their concentration gradient | c. | cotransport
proteins; against their electrochemical gradient | d. | channel proteins; down their electrochemical
gradient | e. | channel proteins down their concentration gradient |
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15.
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The membrane potential of a cell favors
a. | the movement of cations into the cell | b. | the movement of anions into the
cell | c. | the action of an electrogenic pump | d. | the movement of sodium out of the
cell | e. | both b and d |
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16.
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Which of the following describes cotransport?
a. | active transport of two solutes through a cotransport protein | b. | passive transport of
two solutes through a cotransport protein | c. | ion diffusion against the electrochemical
gradient created by an electrogenic pump | d. | a pump such as the sodium-potassium pump
that moves ions in two different directions | e. | transport of one solute against its
concentration gradient in tandem with another that is diffusing down its concentration
gradient |
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17.
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The proton pump in plant cells is the functional equivalent of an animal
cell’s
a. | cotransport mechanism | b. | sodium-potassium pump | c. | contractile vacuole
for osmoregulation | d. | receptor-mediated endocytosis of
cholesterol | e. | ATP pump |
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18.
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Which of the following is an example of active transport?
a. | the transport of glucose when the carrier protein GLUT-1 binds to glucose, changes
shape, and moves glucose across a membrane | b. | the flow of K+ through an open ion channel out
of the cell | c. | the movement of water into a plant cell | d. | the movement of LDL
particles into a cell | e. | the movement of O2 into a cell into
a cell |
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19.
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Pinocytosis involves
a. | the fusion of a newly formed food vacuole with a lysosome | b. | receptor-mediated
endocytosis that involves binding of a ligand | c. | the pinching in of the plasma membrane around
around small droplets of external fluid | d. | the secretion of cell fluid | e. | the accumulation of
specific molecules in a cell |
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20.
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Exocytosis may involve all of the following except
a. | ligands and coated pits | b. | the fusion of a vesicle with the plasma
membrane | c. | a mechanism to export some carbohydrates during the formation of plant cell
walls | d. | a mechanism to rejuvenate the plasma membrane | e. | a means of exporting
large molecules |
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