PCB3023C Exam 2: Cell Biology Comprehensive Quiz 2026 – FGCU
1. Which of the following is the primary component of the plasma membrane’s
bilayer structure?
A. Cholesterol
B. Phospholipids
C. Glycoproteins
D. Peripheral proteins
Answer: B
Rationale: Phospholipids are amphipathic molecules that form the fundamental bilayer
structure of the cell membrane.
2. What is the primary role of cholesterol in the animal cell membrane?
A. Assisting in active transport
B. Regulating membrane fluidity
C. Catalyzing metabolic reactions
D. Acting as a primary energy source
Answer: B
Rationale: Cholesterol acts as a buffer for membrane fluidity, preventing it from becoming
too rigid in cold temperatures or too fluid in high temperatures.
,3. Which transport mechanism moves molecules against their concentration
gradient using ATP?
A. Active transport
B. Facilitated diffusion
C. Simple diffusion
D. Osmosis
Answer: A
Rationale: Active transport requires energy (ATP) to move substances from an area of low
concentration to high concentration.
4. The sodium-potassium pump moves ___ sodium ions out and ___ potassium
ions into the cell.
A. 2; 3
B. 1; 1
C. 3; 2
D. 3; 3
Answer: C
Rationale: The Na+/K+ ATPase pumps 3 Na+ ions out of the cell and 2 K+ ions into the cell
per ATP molecule hydrolyzed.
5. Which organelle is responsible for the majority of ATP production via aerobic
respiration?
A. Mitochondrion
B. Golgi apparatus
C. Lysosome
D. Peroxisome
Answer: A
Rationale: Mitochondria are the ‘powerhouses’ of the cell where oxidative
phosphorylation occurs.
, 6. In glycolysis, what is the net gain of ATP molecules per molecule of glucose?
A. 4
B. 2
C. 32
D. 36
Answer: B
Rationale: While 4 ATP are produced in glycolysis, 2 are consumed in the preparatory
phase, resulting in a net gain of 2 ATP.
7. Where does the Citric Acid Cycle (Krebs Cycle) take place in eukaryotic cells?
A. Cytosol
B. Mitochondrial matrix
C. Inner mitochondrial membrane
D. Intermembrane space
Answer: B
Rationale: The Citric Acid Cycle occurs within the matrix of the mitochondria.
8. Which molecule acts as the final electron acceptor in the mitochondrial
electron transport chain?
A. CO2
B. NAD+
C. Water
D. Oxygen
Answer: D
Rationale: Oxygen (O2) is the final electron acceptor, which then combines with protons to
form water.
1. Which of the following is the primary component of the plasma membrane’s
bilayer structure?
A. Cholesterol
B. Phospholipids
C. Glycoproteins
D. Peripheral proteins
Answer: B
Rationale: Phospholipids are amphipathic molecules that form the fundamental bilayer
structure of the cell membrane.
2. What is the primary role of cholesterol in the animal cell membrane?
A. Assisting in active transport
B. Regulating membrane fluidity
C. Catalyzing metabolic reactions
D. Acting as a primary energy source
Answer: B
Rationale: Cholesterol acts as a buffer for membrane fluidity, preventing it from becoming
too rigid in cold temperatures or too fluid in high temperatures.
,3. Which transport mechanism moves molecules against their concentration
gradient using ATP?
A. Active transport
B. Facilitated diffusion
C. Simple diffusion
D. Osmosis
Answer: A
Rationale: Active transport requires energy (ATP) to move substances from an area of low
concentration to high concentration.
4. The sodium-potassium pump moves ___ sodium ions out and ___ potassium
ions into the cell.
A. 2; 3
B. 1; 1
C. 3; 2
D. 3; 3
Answer: C
Rationale: The Na+/K+ ATPase pumps 3 Na+ ions out of the cell and 2 K+ ions into the cell
per ATP molecule hydrolyzed.
5. Which organelle is responsible for the majority of ATP production via aerobic
respiration?
A. Mitochondrion
B. Golgi apparatus
C. Lysosome
D. Peroxisome
Answer: A
Rationale: Mitochondria are the ‘powerhouses’ of the cell where oxidative
phosphorylation occurs.
, 6. In glycolysis, what is the net gain of ATP molecules per molecule of glucose?
A. 4
B. 2
C. 32
D. 36
Answer: B
Rationale: While 4 ATP are produced in glycolysis, 2 are consumed in the preparatory
phase, resulting in a net gain of 2 ATP.
7. Where does the Citric Acid Cycle (Krebs Cycle) take place in eukaryotic cells?
A. Cytosol
B. Mitochondrial matrix
C. Inner mitochondrial membrane
D. Intermembrane space
Answer: B
Rationale: The Citric Acid Cycle occurs within the matrix of the mitochondria.
8. Which molecule acts as the final electron acceptor in the mitochondrial
electron transport chain?
A. CO2
B. NAD+
C. Water
D. Oxygen
Answer: D
Rationale: Oxygen (O2) is the final electron acceptor, which then combines with protons to
form water.
