PCB3023C Final Exam: Cell Biology 2026 – FGCU
1. Which organelle is primarily responsible for the synthesis of membrane
proteins and secretory proteins?
A. Smooth Endoplasmic Reticulum
B. Golgi Apparatus
C. Rough Endoplasmic Reticulum
D. Lysosome
Answer: C
Rationale: The Rough ER is studded with ribosomes and is the main site for protein
synthesis, especially for proteins destined for membranes or secretion.
2. Which of the following molecules can most easily pass through a cell’s lipid
bilayer by simple diffusion?
A. Oxygen (O2)
B. Sodium ions (Na+)
C. Glucose
D. Amino acids
Answer: A
Rationale: Small non-polar molecules like oxygen and carbon dioxide can diffuse directly
across the hydrophobic core of the lipid bilayer.
,3. What is the primary role of cholesterol in animal cell membranes?
A. Acting as a transport protein
B. Binding to signaling ligands
C. Synthesizing ATP
D. Stabilizing membrane fluidity across temperature changes
Answer: D
Rationale: Cholesterol acts as a fluidity buffer, preventing the membrane from becoming
too rigid at low temperatures and too fluid at high temperatures.
4. The Sodium-Potassium pump (Na+/K+ ATPase) moves ions in which direction?
A. 3 Na+ out, 2 K+ in
B. 2 Na+ out, 3 K+ in
C. 3 Na+ in, 2 K+ out
D. 2 Na+ in, 3 K+ out
Answer: A
Rationale: The pump uses ATP to export three sodium ions and import two potassium ions
against their concentration gradients.
5. In cellular respiration, where does the Citric Acid Cycle (Krebs Cycle) take
place?
A. Cytosol
B. Mitochondrial Intermembrane Space
C. Inner Mitochondrial Membrane
D. Mitochondrial Matrix
Answer: D
Rationale: Glycolysis occurs in the cytosol, while the Citric Acid Cycle occurs within the
matrix of the mitochondria.
, 6. What is the final electron acceptor in the electron transport chain during
aerobic respiration?
A. NAD+
B. FAD
C. Water
D. Oxygen
Answer: D
Rationale: Oxygen acts as the final electron acceptor, combining with electrons and
protons to form water.
7. Which cytoskeletal component is composed of tubulin dimers and aids in
organelle transport?
A. Microfilaments
B. Intermediate Filaments
C. Microtubules
D. Myosin
Answer: C
Rationale: Microtubules are made of alpha and beta-tubulin and serve as tracks for motor
proteins like dynein and kinesin.
8. Which motor protein typically moves cargo toward the minus end (center) of
microtubules?
A. Dynein
B. Kinesin
C. Myosin II
D. Actin
Answer: A
Rationale: Dyneins are minus-end directed motor proteins, whereas most kinesins are
plus-end directed.
1. Which organelle is primarily responsible for the synthesis of membrane
proteins and secretory proteins?
A. Smooth Endoplasmic Reticulum
B. Golgi Apparatus
C. Rough Endoplasmic Reticulum
D. Lysosome
Answer: C
Rationale: The Rough ER is studded with ribosomes and is the main site for protein
synthesis, especially for proteins destined for membranes or secretion.
2. Which of the following molecules can most easily pass through a cell’s lipid
bilayer by simple diffusion?
A. Oxygen (O2)
B. Sodium ions (Na+)
C. Glucose
D. Amino acids
Answer: A
Rationale: Small non-polar molecules like oxygen and carbon dioxide can diffuse directly
across the hydrophobic core of the lipid bilayer.
,3. What is the primary role of cholesterol in animal cell membranes?
A. Acting as a transport protein
B. Binding to signaling ligands
C. Synthesizing ATP
D. Stabilizing membrane fluidity across temperature changes
Answer: D
Rationale: Cholesterol acts as a fluidity buffer, preventing the membrane from becoming
too rigid at low temperatures and too fluid at high temperatures.
4. The Sodium-Potassium pump (Na+/K+ ATPase) moves ions in which direction?
A. 3 Na+ out, 2 K+ in
B. 2 Na+ out, 3 K+ in
C. 3 Na+ in, 2 K+ out
D. 2 Na+ in, 3 K+ out
Answer: A
Rationale: The pump uses ATP to export three sodium ions and import two potassium ions
against their concentration gradients.
5. In cellular respiration, where does the Citric Acid Cycle (Krebs Cycle) take
place?
A. Cytosol
B. Mitochondrial Intermembrane Space
C. Inner Mitochondrial Membrane
D. Mitochondrial Matrix
Answer: D
Rationale: Glycolysis occurs in the cytosol, while the Citric Acid Cycle occurs within the
matrix of the mitochondria.
, 6. What is the final electron acceptor in the electron transport chain during
aerobic respiration?
A. NAD+
B. FAD
C. Water
D. Oxygen
Answer: D
Rationale: Oxygen acts as the final electron acceptor, combining with electrons and
protons to form water.
7. Which cytoskeletal component is composed of tubulin dimers and aids in
organelle transport?
A. Microfilaments
B. Intermediate Filaments
C. Microtubules
D. Myosin
Answer: C
Rationale: Microtubules are made of alpha and beta-tubulin and serve as tracks for motor
proteins like dynein and kinesin.
8. Which motor protein typically moves cargo toward the minus end (center) of
microtubules?
A. Dynein
B. Kinesin
C. Myosin II
D. Actin
Answer: A
Rationale: Dyneins are minus-end directed motor proteins, whereas most kinesins are
plus-end directed.
