1. A cell-free extract was subjected to differential centrifugation. Which of the
following components will require the highest centrifugal force (speed) to form a
pellet?
A) Mitochondria
B) Ribosomes
C) Nuclei
D) Microsomes
Answer: B (Ribosomes are the smallest and least dense
complexes, requiring 150,000 g to pellet).
2. Cells of the pancreas secrete large amounts of digestive enzymes (proteins)
into the intestine. Which of the following organelles would you expect to be
unusually abundant in these pancreatic cells?
A) Smooth ER
B) Rough ER
C) Lysosomes
D) Peroxisomes
Answer: B (Rough ER synthesizes proteins destined for
secretion outside the cell).
3. Examination of a cell reveals a high density of smooth endoplasmic reticulum.
This cell is most likely specialized to perform which of the following functions?
A) Synthesis of large quantities of secretory glycoproteins.
B) Synthesis of lipids and steroid hormones.
C) Destruction of old, damaged organelles via autophagy.
D) Polymerization of tubulin subunits into mitotic spindles.
Answer: B (Smooth ER drives lipid, oil, and steroid hormone
production).
4. According to the endosymbiont theory, which of the following is an expected
characteristic of both mitochondria and chloroplasts?
A) They are bounded by a single membrane layer connected to the ER.
B) They contain autonomous circular DNA and internal ribosomes.
C) They synthesize their own cellulose to protect their boundaries.
D) They completely lack metabolic proteins and enzymes.
Answer: B (Prokaryotic traits like circular DNA and
independent ribosomes support endosymbiosis).
5. A researcher treats a culture of animal cells with Cytochalasin B, a drug that
completely blocks the elongation and function of actin microfilaments. Which of
the following processes will be blocked immediately?
A) The movement of chromosomes during mitotic cell division.
B) The wave-like bending motion of eukaryotic flagella.
C) Amoeboid movement and pseudopodia formation.
D) The dynamic structural maintenance of the nuclear lamina.
Answer: C (Actin microfilaments directly power tension-
bearing, amoeboid crawling, and muscle contraction).
, 6. Vinblastine is a chemotherapy drug that binds to tubulin dimers and prevents
them from polymerizing. Which of the following cellular structures is the
primary target of this drug?
A) Microtubules
B) Microfilaments
C) Intermediate filaments
D) Extracellular matrix
Answer: A (Microtubules are composed entirely of tubulin
protofilaments).
7. In a classic cell fractionation experiment, after the mitochondria are pelleted
at medium speed, what remains in the supernatant fluid?
A) Nuclei and heavy intact cell pieces.
B) Only water and inorganic salts, with no organic complexes.
C) Ribosomes and fragments of the endoplasmic reticulum (microsomes).
D) The central vacuole of animal cells.
Answer: C (Smaller components stay suspended in the
supernatant until higher speeds are applied).
8. Ions travel directly from the cytoplasm of one cardiac muscle cell to the
cytoplasm of an adjacent cell to rapidly propagate electrical impulses that
coordinate a heartbeat. These ions move through:
A) Tight junctions
B) Desmosomes
C) Gap junctions
D) Plasmodesmata
Answer: C (Gap junctions are communicating channels in
animals; plasmodesmata perform this role in plants).
9. A child is diagnosed with a rare genetic condition where a hydrolytic enzyme
responsible for breaking down specific cellular waste molecules is non-
functional. This leads to an accumulation of waste that destroys the cell. Which
organelle is defective?
A) Peroxisome
B) Golgi apparatus
C) Lysosome
D) Smooth ER
Answer: C (Lysosomes are digestive compartments loaded
with macromolecular hydrolytic enzymes).
10. What geometric rule limits how large a single cell can grow while remaining
metabolically efficient?
A) As a cell grows, its surface area increases cubically, while volume increases
quadratically.
B) As a cell grows, its volume increases cubically (r^3), while surface area increases
only quadratically (r^2).
C) Larger cells require heavy metal coatings to survive internal turgor pressure.
D) Volume and surface area shrink simultaneously during metabolic stress.
following components will require the highest centrifugal force (speed) to form a
pellet?
A) Mitochondria
B) Ribosomes
C) Nuclei
D) Microsomes
Answer: B (Ribosomes are the smallest and least dense
complexes, requiring 150,000 g to pellet).
2. Cells of the pancreas secrete large amounts of digestive enzymes (proteins)
into the intestine. Which of the following organelles would you expect to be
unusually abundant in these pancreatic cells?
A) Smooth ER
B) Rough ER
C) Lysosomes
D) Peroxisomes
Answer: B (Rough ER synthesizes proteins destined for
secretion outside the cell).
3. Examination of a cell reveals a high density of smooth endoplasmic reticulum.
This cell is most likely specialized to perform which of the following functions?
A) Synthesis of large quantities of secretory glycoproteins.
B) Synthesis of lipids and steroid hormones.
C) Destruction of old, damaged organelles via autophagy.
D) Polymerization of tubulin subunits into mitotic spindles.
Answer: B (Smooth ER drives lipid, oil, and steroid hormone
production).
4. According to the endosymbiont theory, which of the following is an expected
characteristic of both mitochondria and chloroplasts?
A) They are bounded by a single membrane layer connected to the ER.
B) They contain autonomous circular DNA and internal ribosomes.
C) They synthesize their own cellulose to protect their boundaries.
D) They completely lack metabolic proteins and enzymes.
Answer: B (Prokaryotic traits like circular DNA and
independent ribosomes support endosymbiosis).
5. A researcher treats a culture of animal cells with Cytochalasin B, a drug that
completely blocks the elongation and function of actin microfilaments. Which of
the following processes will be blocked immediately?
A) The movement of chromosomes during mitotic cell division.
B) The wave-like bending motion of eukaryotic flagella.
C) Amoeboid movement and pseudopodia formation.
D) The dynamic structural maintenance of the nuclear lamina.
Answer: C (Actin microfilaments directly power tension-
bearing, amoeboid crawling, and muscle contraction).
, 6. Vinblastine is a chemotherapy drug that binds to tubulin dimers and prevents
them from polymerizing. Which of the following cellular structures is the
primary target of this drug?
A) Microtubules
B) Microfilaments
C) Intermediate filaments
D) Extracellular matrix
Answer: A (Microtubules are composed entirely of tubulin
protofilaments).
7. In a classic cell fractionation experiment, after the mitochondria are pelleted
at medium speed, what remains in the supernatant fluid?
A) Nuclei and heavy intact cell pieces.
B) Only water and inorganic salts, with no organic complexes.
C) Ribosomes and fragments of the endoplasmic reticulum (microsomes).
D) The central vacuole of animal cells.
Answer: C (Smaller components stay suspended in the
supernatant until higher speeds are applied).
8. Ions travel directly from the cytoplasm of one cardiac muscle cell to the
cytoplasm of an adjacent cell to rapidly propagate electrical impulses that
coordinate a heartbeat. These ions move through:
A) Tight junctions
B) Desmosomes
C) Gap junctions
D) Plasmodesmata
Answer: C (Gap junctions are communicating channels in
animals; plasmodesmata perform this role in plants).
9. A child is diagnosed with a rare genetic condition where a hydrolytic enzyme
responsible for breaking down specific cellular waste molecules is non-
functional. This leads to an accumulation of waste that destroys the cell. Which
organelle is defective?
A) Peroxisome
B) Golgi apparatus
C) Lysosome
D) Smooth ER
Answer: C (Lysosomes are digestive compartments loaded
with macromolecular hydrolytic enzymes).
10. What geometric rule limits how large a single cell can grow while remaining
metabolically efficient?
A) As a cell grows, its surface area increases cubically, while volume increases
quadratically.
B) As a cell grows, its volume increases cubically (r^3), while surface area increases
only quadratically (r^2).
C) Larger cells require heavy metal coatings to survive internal turgor pressure.
D) Volume and surface area shrink simultaneously during metabolic stress.
