PCB3023C Cell Biology Final Exam Prep 2026 |FGCU
1. What is the primary role of cholesterol in the animal cell membrane?
A. It regulates membrane fluidity across different temperatures.
B. It acts as a channel for ion transport.
C. It serves as the main site for protein synthesis.
D. It attaches the membrane to the cell wall.
Answer: A
Rationale: Cholesterol buffers the fluidity of the plasma membrane, preventing it from
becoming too rigid in cold temperatures and too fluid in high temperatures.
2. Which organelle is responsible for the modification and sorting of proteins
received from the endoplasmic reticulum?
A. Lysosome
B. Peroxisome
C. Mitochondrion
D. Golgi apparatus
Answer: D
Rationale: The Golgi apparatus functions as a processing and dispatching station for
proteins and lipids synthesized in the ER.
3. During which phase of the cell cycle is DNA replicated?
A. G1 phase
B. G2 phase
C. S phase
D. M phase
Answer: C
,Rationale: The S phase (Synthesis phase) is dedicated to the replication of the cell’s genetic
material.
4. Which of the following describes the function of the signal recognition
particle (SRP)?
A. Degrading misfolded proteins in the cytosol.
B. Transporting mRNA from the nucleus to the cytoplasm.
C. Directing ribosomes to the endoplasmic reticulum membrane.
D. Catalyzing the formation of peptide bonds.
Answer: C
Rationale: The SRP recognizes the signal sequence on a growing polypeptide and targets
the ribosome to the ER for co-translational translocation.
5. Which cytoskeletal element is composed of actin subunits and is involved in
cell crawling?
A. Microtubules
B. Microfilaments
C. Intermediate filaments
D. Lamins
Answer: B
Rationale: Microfilaments, also known as actin filaments, are dynamic structures essential
for cell movement and cytokinesis.
6. In the process of oxidative phosphorylation, what is the final electron
acceptor?
A. NAD+
B. Carbon dioxide
C. Water
D. Oxygen
Answer: D
, Rationale: Oxygen accepts electrons at the end of the electron transport chain to form
water, driving the production of ATP.
7. What is the primary function of lysosomes?
A. Lipid synthesis
B. Intracellular digestion
C. Ribosome assembly
D. Energy production
Answer: B
Rationale: Lysosomes contain hydrolytic enzymes that break down macromolecules, old
organelles, and foreign substances.
8. Which of the following is a second messenger in G-protein coupled receptor
(GPCR) signaling?
A. cyclic AMP (cAMP)
B. Adenylate cyclase
C. GTP
D. Tyrosine kinase
Answer: A
Rationale: cAMP is a common second messenger that relays signals from the cell surface to
internal targets.
9. Which process describes the movement of molecules against their
concentration gradient using ATP?
A. Simple diffusion
B. Facilitated diffusion
C. Active transport
D. Osmosis
Answer: C
1. What is the primary role of cholesterol in the animal cell membrane?
A. It regulates membrane fluidity across different temperatures.
B. It acts as a channel for ion transport.
C. It serves as the main site for protein synthesis.
D. It attaches the membrane to the cell wall.
Answer: A
Rationale: Cholesterol buffers the fluidity of the plasma membrane, preventing it from
becoming too rigid in cold temperatures and too fluid in high temperatures.
2. Which organelle is responsible for the modification and sorting of proteins
received from the endoplasmic reticulum?
A. Lysosome
B. Peroxisome
C. Mitochondrion
D. Golgi apparatus
Answer: D
Rationale: The Golgi apparatus functions as a processing and dispatching station for
proteins and lipids synthesized in the ER.
3. During which phase of the cell cycle is DNA replicated?
A. G1 phase
B. G2 phase
C. S phase
D. M phase
Answer: C
,Rationale: The S phase (Synthesis phase) is dedicated to the replication of the cell’s genetic
material.
4. Which of the following describes the function of the signal recognition
particle (SRP)?
A. Degrading misfolded proteins in the cytosol.
B. Transporting mRNA from the nucleus to the cytoplasm.
C. Directing ribosomes to the endoplasmic reticulum membrane.
D. Catalyzing the formation of peptide bonds.
Answer: C
Rationale: The SRP recognizes the signal sequence on a growing polypeptide and targets
the ribosome to the ER for co-translational translocation.
5. Which cytoskeletal element is composed of actin subunits and is involved in
cell crawling?
A. Microtubules
B. Microfilaments
C. Intermediate filaments
D. Lamins
Answer: B
Rationale: Microfilaments, also known as actin filaments, are dynamic structures essential
for cell movement and cytokinesis.
6. In the process of oxidative phosphorylation, what is the final electron
acceptor?
A. NAD+
B. Carbon dioxide
C. Water
D. Oxygen
Answer: D
, Rationale: Oxygen accepts electrons at the end of the electron transport chain to form
water, driving the production of ATP.
7. What is the primary function of lysosomes?
A. Lipid synthesis
B. Intracellular digestion
C. Ribosome assembly
D. Energy production
Answer: B
Rationale: Lysosomes contain hydrolytic enzymes that break down macromolecules, old
organelles, and foreign substances.
8. Which of the following is a second messenger in G-protein coupled receptor
(GPCR) signaling?
A. cyclic AMP (cAMP)
B. Adenylate cyclase
C. GTP
D. Tyrosine kinase
Answer: A
Rationale: cAMP is a common second messenger that relays signals from the cell surface to
internal targets.
9. Which process describes the movement of molecules against their
concentration gradient using ATP?
A. Simple diffusion
B. Facilitated diffusion
C. Active transport
D. Osmosis
Answer: C
