PASSPOINT PRO SOUTHEASTERN LOUISIANA UNIVERSITY
GBIO 200
CELL BIOLOGY
EXAM 4 - 125Q
Membrane structure, transport, vesicular traffic, signal transduction,
and membrane excitability
125 A-D FULL
ORIGINAL QUESTIONS ANSWER CHOICES RATIONALES
Built for focused exam review
Concept recall + application questions
Immediate answers with concise explanations
Compact layout for fast review and printing
Original practice content aligned to GBIO 200 topics
PassPoint Pro | Practice. Understand. Perform. GBIO 200
,PASSPOINT PRO | GBIO 200 CELL BIOLOGY EXAM 4 - 125Q
HOW TO USE THIS PRACTICE SET
Format: Each item includes four answer choices followed immediately by the correct answer and an explanation. Best use:
Complete a first pass without reading the answer, then use each rationale to repair weak concepts. Coverage: Membrane
structure, transport, vesicular traffic, signal transduction, and membrane excitability.
QUESTIONS 1-25
1 Which term or structure best matches the following description: net movement of water across a
selectively permeable membrane toward the side with lower water potential or higher effective solute
concentration?
A. simple diffusion
B. ion channel
C. Na+/K+ ATPase
D. osmosis
Answer: D
Explanation: Osmosis is correct because it is net movement of water across a selectively permeable membrane toward the side with
lower water potential or higher effective solute concentration. Water enters a cell placed in a hypotonic solution. This match is more
specific than the related alternatives, which describe different structures, molecules, or processes.
2 A student is reviewing carrier protein. Which description is most accurate?
A. net movement of molecules down a concentration gradient directly through the lipid bilayer without a transport protein
B. a membrane channel that greatly increases water permeability
C. a selective membrane pore that permits ions to move rapidly down their electrochemical gradients
D. a transporter that binds solute and changes conformation to move it across a membrane
Answer: D
Explanation: The correct description of carrier protein is that it is a transporter that binds solute and changes conformation to move it
across a membrane. A membrane protein alternates between outward-facing and inward-facing conformations while transporting glucose.
The other choices define different concepts and therefore do not fit this term.
3 A receptor signal is relayed through Raf, MEK, and ERK. What is the best explanation for the finding?
A. signal amplification
B. MAP kinase cascade
C. protein phosphatase
D. adenylyl cyclase
Answer: B
Explanation: Map kinase cascade best explains the observation because it is a series of protein kinases that sequentially activate one
another and can alter gene expression and cell behavior. The scenario is a direct application of that function or mechanism. The
distractors are related cell-biology concepts but do not account for the key feature described.
Original practice questions with explanations Page 2
,PASSPOINT PRO | GBIO 200 CELL BIOLOGY EXAM 4 - 125Q
4 A cell undergoes the following change: Kinase inhibition would block recruitment and activation of
downstream signaling proteins. Which target was most likely altered?
A. receptor tyrosine kinase
B. phospholipase C
C. adenylyl cyclase
D. cAMP
Answer: A
Explanation: Receptor tyrosine kinase is the best match. It is a cell-surface receptor that often dimerizes and autophosphorylates
tyrosines after ligand binding, so the stated consequence follows directly when its function is changed. The other options can influence
cellular behavior, but they do not most directly predict this specific outcome.
5 Which term-description pairing is correct?
A. facilitated diffusion - a neurotransmitter released at many synapses, including the neuromuscular junction
B. action potential - a rapid, regenerative change in membrane potential driven by voltage-gated ion channels
C. symport - passive movement down an electrochemical gradient through a membrane channel or carrier
D. acetylcholine - coupled transport in which two solutes move through one transporter in the same direction
Answer: B
Explanation: The correct pairing is action potential with its defining feature: a rapid, regenerative change in membrane potential driven by
voltage-gated ion channels. A neuron depolarizes past threshold and an electrical signal propagates along the axon. The remaining pairs
intentionally mismatch a term with the description of a different concept.
6 Which option is most accurately defined as the voltage difference across a plasma membrane produced
by unequal ion distributions and selective permeability?
A. membrane potential
B. osmosis
C. ion channel
D. carrier protein
Answer: A
Explanation: Membrane potential is correct because it is the voltage difference across a plasma membrane produced by unequal ion
distributions and selective permeability. The cytosol is electrically negative relative to the extracellular fluid. This match is more specific
than the related alternatives, which describe different structures, molecules, or processes.
7 Which statement best describes fluid mosaic model?
A. a membrane lipid with a hydrophilic head and hydrophobic tails that self-assembles into bilayers
B. the concept that membranes are dynamic lipid bilayers containing mobile proteins and other components
C. a sterol interspersed among phospholipids that buffers membrane fluidity and decreases permeability to some small molecules
D. a protein loosely associated with the membrane surface or with integral proteins rather than embedded deeply in the bilayer
Answer: B
Explanation: The correct description of fluid mosaic model is that it is the concept that membranes are dynamic lipid bilayers containing
mobile proteins and other components. Many membrane proteins diffuse laterally within a flexible lipid bilayer. The other choices define
different concepts and therefore do not fit this term.
Original practice questions with explanations Page 3
, PASSPOINT PRO | GBIO 200 CELL BIOLOGY EXAM 4 - 125Q
8 Binding of a few hormone molecules leads to production of thousands of second-messenger molecules.
Which structure or process is most directly involved?
A. Ras
B. receptor tyrosine kinase
C. heterotrimeric G protein
D. signal amplification
Answer: D
Explanation: Signal amplification best explains the observation because it is the multiplication of a signal when one activated molecule
triggers activation of many downstream molecules. The scenario is a direct application of that function or mechanism. The distractors are
related cell-biology concepts but do not account for the key feature described.
9 A selective perturbation causes this outcome: Preventing nucleotide exchange would keep the complex
largely inactive. Which process or structure is the best match?
A. PI3K-Akt pathway
B. receptor tyrosine kinase
C. IP3
D. heterotrimeric G protein
Answer: D
Explanation: Heterotrimeric g protein is the best match. It is a membrane-associated signaling complex with alpha, beta, and gamma
subunits that relays signals from GPCRs, so the stated consequence follows directly when its function is changed. The other options can
influence cellular behavior, but they do not most directly predict this specific outcome.
10 Which term-description pairing is correct?
A. amphipathic phospholipid - a protein loosely associated with the membrane surface or with integral proteins rather than
embedded deeply in the bilayer
B. glycoprotein - a protein carrying covalently attached carbohydrate chains, commonly exposed on the cell surface or lumenal side
of organelles
C. fluid mosaic model - a membrane lipid with a hydrophilic head and hydrophobic tails that self-assembles into bilayers
D. peripheral membrane protein - the concept that membranes are dynamic lipid bilayers containing mobile proteins and other
components
Answer: B
Explanation: The correct pairing is glycoprotein with its defining feature: a protein carrying covalently attached carbohydrate chains,
commonly exposed on the cell surface or lumenal side of organelles. A membrane receptor has short oligosaccharides projecting into the
extracellular space. The remaining pairs intentionally mismatch a term with the description of a different concept.
11 Identify the concept described here: passive movement down an electrochemical gradient through a
membrane channel or carrier.
A. symport
B. facilitated diffusion
C. ion channel
D. simple diffusion
Answer: B
Explanation: Facilitated diffusion is correct because it is passive movement down an electrochemical gradient through a membrane
channel or carrier. Glucose enters a cell through a specific transporter without direct ATP hydrolysis. This match is more specific than the
related alternatives, which describe different structures, molecules, or processes.
Original practice questions with explanations Page 4
GBIO 200
CELL BIOLOGY
EXAM 4 - 125Q
Membrane structure, transport, vesicular traffic, signal transduction,
and membrane excitability
125 A-D FULL
ORIGINAL QUESTIONS ANSWER CHOICES RATIONALES
Built for focused exam review
Concept recall + application questions
Immediate answers with concise explanations
Compact layout for fast review and printing
Original practice content aligned to GBIO 200 topics
PassPoint Pro | Practice. Understand. Perform. GBIO 200
,PASSPOINT PRO | GBIO 200 CELL BIOLOGY EXAM 4 - 125Q
HOW TO USE THIS PRACTICE SET
Format: Each item includes four answer choices followed immediately by the correct answer and an explanation. Best use:
Complete a first pass without reading the answer, then use each rationale to repair weak concepts. Coverage: Membrane
structure, transport, vesicular traffic, signal transduction, and membrane excitability.
QUESTIONS 1-25
1 Which term or structure best matches the following description: net movement of water across a
selectively permeable membrane toward the side with lower water potential or higher effective solute
concentration?
A. simple diffusion
B. ion channel
C. Na+/K+ ATPase
D. osmosis
Answer: D
Explanation: Osmosis is correct because it is net movement of water across a selectively permeable membrane toward the side with
lower water potential or higher effective solute concentration. Water enters a cell placed in a hypotonic solution. This match is more
specific than the related alternatives, which describe different structures, molecules, or processes.
2 A student is reviewing carrier protein. Which description is most accurate?
A. net movement of molecules down a concentration gradient directly through the lipid bilayer without a transport protein
B. a membrane channel that greatly increases water permeability
C. a selective membrane pore that permits ions to move rapidly down their electrochemical gradients
D. a transporter that binds solute and changes conformation to move it across a membrane
Answer: D
Explanation: The correct description of carrier protein is that it is a transporter that binds solute and changes conformation to move it
across a membrane. A membrane protein alternates between outward-facing and inward-facing conformations while transporting glucose.
The other choices define different concepts and therefore do not fit this term.
3 A receptor signal is relayed through Raf, MEK, and ERK. What is the best explanation for the finding?
A. signal amplification
B. MAP kinase cascade
C. protein phosphatase
D. adenylyl cyclase
Answer: B
Explanation: Map kinase cascade best explains the observation because it is a series of protein kinases that sequentially activate one
another and can alter gene expression and cell behavior. The scenario is a direct application of that function or mechanism. The
distractors are related cell-biology concepts but do not account for the key feature described.
Original practice questions with explanations Page 2
,PASSPOINT PRO | GBIO 200 CELL BIOLOGY EXAM 4 - 125Q
4 A cell undergoes the following change: Kinase inhibition would block recruitment and activation of
downstream signaling proteins. Which target was most likely altered?
A. receptor tyrosine kinase
B. phospholipase C
C. adenylyl cyclase
D. cAMP
Answer: A
Explanation: Receptor tyrosine kinase is the best match. It is a cell-surface receptor that often dimerizes and autophosphorylates
tyrosines after ligand binding, so the stated consequence follows directly when its function is changed. The other options can influence
cellular behavior, but they do not most directly predict this specific outcome.
5 Which term-description pairing is correct?
A. facilitated diffusion - a neurotransmitter released at many synapses, including the neuromuscular junction
B. action potential - a rapid, regenerative change in membrane potential driven by voltage-gated ion channels
C. symport - passive movement down an electrochemical gradient through a membrane channel or carrier
D. acetylcholine - coupled transport in which two solutes move through one transporter in the same direction
Answer: B
Explanation: The correct pairing is action potential with its defining feature: a rapid, regenerative change in membrane potential driven by
voltage-gated ion channels. A neuron depolarizes past threshold and an electrical signal propagates along the axon. The remaining pairs
intentionally mismatch a term with the description of a different concept.
6 Which option is most accurately defined as the voltage difference across a plasma membrane produced
by unequal ion distributions and selective permeability?
A. membrane potential
B. osmosis
C. ion channel
D. carrier protein
Answer: A
Explanation: Membrane potential is correct because it is the voltage difference across a plasma membrane produced by unequal ion
distributions and selective permeability. The cytosol is electrically negative relative to the extracellular fluid. This match is more specific
than the related alternatives, which describe different structures, molecules, or processes.
7 Which statement best describes fluid mosaic model?
A. a membrane lipid with a hydrophilic head and hydrophobic tails that self-assembles into bilayers
B. the concept that membranes are dynamic lipid bilayers containing mobile proteins and other components
C. a sterol interspersed among phospholipids that buffers membrane fluidity and decreases permeability to some small molecules
D. a protein loosely associated with the membrane surface or with integral proteins rather than embedded deeply in the bilayer
Answer: B
Explanation: The correct description of fluid mosaic model is that it is the concept that membranes are dynamic lipid bilayers containing
mobile proteins and other components. Many membrane proteins diffuse laterally within a flexible lipid bilayer. The other choices define
different concepts and therefore do not fit this term.
Original practice questions with explanations Page 3
, PASSPOINT PRO | GBIO 200 CELL BIOLOGY EXAM 4 - 125Q
8 Binding of a few hormone molecules leads to production of thousands of second-messenger molecules.
Which structure or process is most directly involved?
A. Ras
B. receptor tyrosine kinase
C. heterotrimeric G protein
D. signal amplification
Answer: D
Explanation: Signal amplification best explains the observation because it is the multiplication of a signal when one activated molecule
triggers activation of many downstream molecules. The scenario is a direct application of that function or mechanism. The distractors are
related cell-biology concepts but do not account for the key feature described.
9 A selective perturbation causes this outcome: Preventing nucleotide exchange would keep the complex
largely inactive. Which process or structure is the best match?
A. PI3K-Akt pathway
B. receptor tyrosine kinase
C. IP3
D. heterotrimeric G protein
Answer: D
Explanation: Heterotrimeric g protein is the best match. It is a membrane-associated signaling complex with alpha, beta, and gamma
subunits that relays signals from GPCRs, so the stated consequence follows directly when its function is changed. The other options can
influence cellular behavior, but they do not most directly predict this specific outcome.
10 Which term-description pairing is correct?
A. amphipathic phospholipid - a protein loosely associated with the membrane surface or with integral proteins rather than
embedded deeply in the bilayer
B. glycoprotein - a protein carrying covalently attached carbohydrate chains, commonly exposed on the cell surface or lumenal side
of organelles
C. fluid mosaic model - a membrane lipid with a hydrophilic head and hydrophobic tails that self-assembles into bilayers
D. peripheral membrane protein - the concept that membranes are dynamic lipid bilayers containing mobile proteins and other
components
Answer: B
Explanation: The correct pairing is glycoprotein with its defining feature: a protein carrying covalently attached carbohydrate chains,
commonly exposed on the cell surface or lumenal side of organelles. A membrane receptor has short oligosaccharides projecting into the
extracellular space. The remaining pairs intentionally mismatch a term with the description of a different concept.
11 Identify the concept described here: passive movement down an electrochemical gradient through a
membrane channel or carrier.
A. symport
B. facilitated diffusion
C. ion channel
D. simple diffusion
Answer: B
Explanation: Facilitated diffusion is correct because it is passive movement down an electrochemical gradient through a membrane
channel or carrier. Glucose enters a cell through a specific transporter without direct ATP hydrolysis. This match is more specific than the
related alternatives, which describe different structures, molecules, or processes.
Original practice questions with explanations Page 4
