Cell Biology 112 Final Exam PCC | 2025/2026
Edition | 70 Original Questions with Evidence-
Based Verified Answers Pasadena City College |
Comprehensive Cell Biology Assessment | Expert-
Aligned Q&A | Exam-Ready Format
Introduction
This 70-question original competency assessment focuses on cell biology
domains, emphasizing membrane structure and transport, cellular energy and
metabolism, genetic information flow, cell cycle and division, cell signaling
and communication, and cellular research techniques. Items integrate
molecular mechanisms, metabolic pathways, experimental design, and data
analysis aligned with current PCC curriculum standards. The assessment
prepares students for comprehensive program evaluation and demonstrates
mastery in cellular structures, functions, and molecular processes.
Content Area Overview: 70 Questions
Content Area Questions Key Topics Weight
Lipid bilayers, membrane
Membrane
proteins, passive/active
Structure and 14 20%
transport, ion channels,
Transport
endocytosis, exocytosis
Glycolysis, TCA cycle,
oxidative phosphorylation,
Cellular Energy
14 photosynthesis, enzyme 20%
and Metabolism
kinetics, metabolic
regulation
,Content Area Questions Key Topics Weight
DNA replication,
Genetic transcription, translation,
14 20%
Information Flow gene regulation, epigenetics,
RNA processing
Mitosis, meiosis, cell cycle
Cell Cycle and regulation, checkpoints,
12 17%
Division apoptosis, cancer biology,
stem cells
Signal transduction,
Cell Signaling and receptors, second
8 11%
Communication messengers, GPCRs, RTKs,
signaling cascades
Microscopy, cell
fractionation, PCR,
Cellular Research
8 electrophoresis, flow 12%
Techniques
cytometry, cryo-EM, single-
cell analysis
Examination Questions
Domain: Membrane Structure and Transport
1. Which phospholipid head-group is most abundant in the inner leaflet
of human erythrocytes?
• a) Phosphatidylcholine
• b) Phosphatidylethanolamine
• c) Phosphatidylinositol
• d) Sphingomyelin
,Correct Answer: B
Rationale: The inner leaflet of erythrocyte membranes is enriched in
phosphatidylethanolamine and phosphatidylserine, while the outer leaflet
contains more phosphatidylcholine and sphingomyelin.
Why Wrong: A is more abundant in the outer leaflet; C is a minor component;
D is more abundant in the outer leaflet.
Reference: Alberts Molecular Biology of the Cell; membrane asymmetry.
2. What is the primary function of the Na⁺/K⁺ ATPase pump in animal
cells?
• a) Maintains electrochemical gradients by pumping Na⁺ out and K⁺
in
• b) Pumps Na⁺ into cells and K⁺ out
• c) Facilitates diffusion of Na⁺ and K⁺
• d) Functions only in neurons
Correct Answer: A
Rationale: The Na⁺/K⁺ ATPase transports 3 Na⁺ out and 2 K⁺ in per ATP
hydrolyzed, maintaining gradients essential for numerous cellular functions.
Why Wrong: B is the opposite direction; C describes passive transport; D is
incorrect as it is ubiquitous.
Reference: Molecular mechanisms of ion transport.
3. Which membrane component is primarily responsible for the fluidity
of the lipid bilayer?
• a) Integral proteins
• b) Unsaturated fatty acid tails
• c) Peripheral proteins
• d) Cholesterol
, Correct Answer: B
Rationale: Unsaturated fatty acid tails with cis-double bonds create kinks that
prevent tight packing, increasing membrane fluidity.
Why Wrong: A and C are proteins; D modulates fluidity but is not the primary
factor.
Reference: Membrane fluidity; lipid bilayer properties.
4. A researcher observes that a cell's membrane becomes less fluid as
temperature decreases. Which membrane adaptation would most likely
restore fluidity?
• a) Increase cholesterol content
• b) Increase unsaturated fatty acid content
• c) Decrease protein content
• d) Increase saturated fatty acid content
Correct Answer: B
Rationale: Increasing unsaturated fatty acids maintains membrane fluidity at
lower temperatures by preventing tight packing.
Why Wrong: A can buffer but not the primary mechanism; C is unrelated; D
would decrease fluidity further.
Reference: Homeoviscous adaptation; membrane lipid composition.
5. Which type of membrane transport requires direct energy from ATP
hydrolysis?
• a) Facilitated diffusion
• b) Primary active transport
• c) Secondary active transport
• d) Simple diffusion
Edition | 70 Original Questions with Evidence-
Based Verified Answers Pasadena City College |
Comprehensive Cell Biology Assessment | Expert-
Aligned Q&A | Exam-Ready Format
Introduction
This 70-question original competency assessment focuses on cell biology
domains, emphasizing membrane structure and transport, cellular energy and
metabolism, genetic information flow, cell cycle and division, cell signaling
and communication, and cellular research techniques. Items integrate
molecular mechanisms, metabolic pathways, experimental design, and data
analysis aligned with current PCC curriculum standards. The assessment
prepares students for comprehensive program evaluation and demonstrates
mastery in cellular structures, functions, and molecular processes.
Content Area Overview: 70 Questions
Content Area Questions Key Topics Weight
Lipid bilayers, membrane
Membrane
proteins, passive/active
Structure and 14 20%
transport, ion channels,
Transport
endocytosis, exocytosis
Glycolysis, TCA cycle,
oxidative phosphorylation,
Cellular Energy
14 photosynthesis, enzyme 20%
and Metabolism
kinetics, metabolic
regulation
,Content Area Questions Key Topics Weight
DNA replication,
Genetic transcription, translation,
14 20%
Information Flow gene regulation, epigenetics,
RNA processing
Mitosis, meiosis, cell cycle
Cell Cycle and regulation, checkpoints,
12 17%
Division apoptosis, cancer biology,
stem cells
Signal transduction,
Cell Signaling and receptors, second
8 11%
Communication messengers, GPCRs, RTKs,
signaling cascades
Microscopy, cell
fractionation, PCR,
Cellular Research
8 electrophoresis, flow 12%
Techniques
cytometry, cryo-EM, single-
cell analysis
Examination Questions
Domain: Membrane Structure and Transport
1. Which phospholipid head-group is most abundant in the inner leaflet
of human erythrocytes?
• a) Phosphatidylcholine
• b) Phosphatidylethanolamine
• c) Phosphatidylinositol
• d) Sphingomyelin
,Correct Answer: B
Rationale: The inner leaflet of erythrocyte membranes is enriched in
phosphatidylethanolamine and phosphatidylserine, while the outer leaflet
contains more phosphatidylcholine and sphingomyelin.
Why Wrong: A is more abundant in the outer leaflet; C is a minor component;
D is more abundant in the outer leaflet.
Reference: Alberts Molecular Biology of the Cell; membrane asymmetry.
2. What is the primary function of the Na⁺/K⁺ ATPase pump in animal
cells?
• a) Maintains electrochemical gradients by pumping Na⁺ out and K⁺
in
• b) Pumps Na⁺ into cells and K⁺ out
• c) Facilitates diffusion of Na⁺ and K⁺
• d) Functions only in neurons
Correct Answer: A
Rationale: The Na⁺/K⁺ ATPase transports 3 Na⁺ out and 2 K⁺ in per ATP
hydrolyzed, maintaining gradients essential for numerous cellular functions.
Why Wrong: B is the opposite direction; C describes passive transport; D is
incorrect as it is ubiquitous.
Reference: Molecular mechanisms of ion transport.
3. Which membrane component is primarily responsible for the fluidity
of the lipid bilayer?
• a) Integral proteins
• b) Unsaturated fatty acid tails
• c) Peripheral proteins
• d) Cholesterol
, Correct Answer: B
Rationale: Unsaturated fatty acid tails with cis-double bonds create kinks that
prevent tight packing, increasing membrane fluidity.
Why Wrong: A and C are proteins; D modulates fluidity but is not the primary
factor.
Reference: Membrane fluidity; lipid bilayer properties.
4. A researcher observes that a cell's membrane becomes less fluid as
temperature decreases. Which membrane adaptation would most likely
restore fluidity?
• a) Increase cholesterol content
• b) Increase unsaturated fatty acid content
• c) Decrease protein content
• d) Increase saturated fatty acid content
Correct Answer: B
Rationale: Increasing unsaturated fatty acids maintains membrane fluidity at
lower temperatures by preventing tight packing.
Why Wrong: A can buffer but not the primary mechanism; C is unrelated; D
would decrease fluidity further.
Reference: Homeoviscous adaptation; membrane lipid composition.
5. Which type of membrane transport requires direct energy from ATP
hydrolysis?
• a) Facilitated diffusion
• b) Primary active transport
• c) Secondary active transport
• d) Simple diffusion
