MCB 252 Cell Biology
MCB 252 - CELL BIOLOGY | VERIFIED EXAM QUESTIONS
AND ANSWERS - LATEST VERSION 2026/2027
MCB 252
CELL BIOLOGY
1. Approximately what is the resolution limit of a standard light
microscope?
A. 0.2 nm
B. 2 nm
C. 0.2 µm
D. 20 µm
ANSWER : C. 0.2 µm
Explanation: The resolution limit of a light microscope is about 0.2 µm
(200 nm), set by the wavelength of visible light.
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, MCB 252 Cell Biology
2. Phase-contrast microscopy is most useful for observing:
A. Living, unstained cells
B. Cell-surface topography in 3D
C. Fixed, sectioned tissue only
D. Individual atoms
ANSWER : A. Living, unstained cells
Explanation: Phase-contrast converts differences in refractive index
into differences in contrast, so live unstained cells can be seen.
3. Which technique is best suited to following a specific protein inside living
cells?
A. Western blotting
B. Differential centrifugation
C. Fusion of the protein to green fluorescent protein (GFP)
D. Negative staining
ANSWER : C. Fusion of the protein to green fluorescent protein
(GFP)
Explanation: A GFP fusion lets the protein be tracked by fluorescence
microscopy in live cells.
4. Scanning electron microscopy (SEM) differs from transmission electron
microscopy (TEM) in that SEM:
A. Has a lower resolution than a light microscope
B. Passes electrons through a thin section
C. Cannot be used on biological samples
D. Provides images of surface topography
ANSWER : D. Provides images of surface topography
Explanation: SEM scans the specimen surface with an electron beam
and produces a 3D-like image of the surface.
Page 2 of 57
, MCB 252 Cell Biology
5. Differential centrifugation separates cell components mainly according to
their:
A. Hydrophobicity
B. Size and density
C. Charge
D. Amino acid sequence
ANSWER : B. Size and density
Explanation: Larger and denser particles sediment at lower speeds, so
organelles pellet in a predictable order.
6. Which cell component is usually found in the pellet after the first, low-
speed spin of a homogenate?
A. Microsomes
B. Soluble enzymes
C. Nuclei and unbroken cells
D. Ribosomes
ANSWER : C. Nuclei and unbroken cells
Explanation: Nuclei and unbroken cells are the heaviest components
and pellet first.
7. Equilibrium density-gradient centrifugation separates particles on the
basis of:
A. Buoyant density
B. Isoelectric point
C. Binding affinity
D. Molecular weight only
ANSWER : A. Buoyant density
Explanation: Particles migrate until they reach the point in the
gradient equal to their own buoyant density.
Page 3 of 57
, MCB 252 Cell Biology
8. Western blotting is used to detect:
A. Specific RNA molecules
B. Specific proteins using antibodies
C. Specific DNA sequences
D. Lipids in membranes
ANSWER : B. Specific proteins using antibodies
Explanation: Proteins are separated by gel electrophoresis, transferred
to a membrane and detected with specific antibodies.
9. The main advantage of confocal microscopy is that it:
A. Magnifies more than an electron microscope
B. Works only on dead cells
C. Removes out-of-focus light to give optical sections
D. Requires no fluorescent labels
ANSWER : C. Removes out-of-focus light to give optical sections
Explanation: A pinhole blocks out-of-focus light, giving sharp optical
sections of thick specimens.
10. Which statement is a principle of the cell theory attributed to Virchow?
A. All cells contain a nucleus
B. All cells arise from pre-existing cells
C. Cells can arise by spontaneous generation
D. Viruses are the smallest cells
ANSWER : B. All cells arise from pre-existing cells
Explanation: Virchow's contribution was the statement that every cell
comes from a pre-existing cell.
11. The defining feature of a prokaryotic cell is the absence of:
A. A cell wall
B. Ribosomes
C. A plasma membrane
D. A membrane-bound nucleus
ANSWER : D. A membrane-bound nucleus
Explanation: Prokaryotes lack a nucleus enclosed by a nuclear
envelope; their DNA lies in the nucleoid.
Page 4 of 57
MCB 252 - CELL BIOLOGY | VERIFIED EXAM QUESTIONS
AND ANSWERS - LATEST VERSION 2026/2027
MCB 252
CELL BIOLOGY
1. Approximately what is the resolution limit of a standard light
microscope?
A. 0.2 nm
B. 2 nm
C. 0.2 µm
D. 20 µm
ANSWER : C. 0.2 µm
Explanation: The resolution limit of a light microscope is about 0.2 µm
(200 nm), set by the wavelength of visible light.
Page 1 of 57
, MCB 252 Cell Biology
2. Phase-contrast microscopy is most useful for observing:
A. Living, unstained cells
B. Cell-surface topography in 3D
C. Fixed, sectioned tissue only
D. Individual atoms
ANSWER : A. Living, unstained cells
Explanation: Phase-contrast converts differences in refractive index
into differences in contrast, so live unstained cells can be seen.
3. Which technique is best suited to following a specific protein inside living
cells?
A. Western blotting
B. Differential centrifugation
C. Fusion of the protein to green fluorescent protein (GFP)
D. Negative staining
ANSWER : C. Fusion of the protein to green fluorescent protein
(GFP)
Explanation: A GFP fusion lets the protein be tracked by fluorescence
microscopy in live cells.
4. Scanning electron microscopy (SEM) differs from transmission electron
microscopy (TEM) in that SEM:
A. Has a lower resolution than a light microscope
B. Passes electrons through a thin section
C. Cannot be used on biological samples
D. Provides images of surface topography
ANSWER : D. Provides images of surface topography
Explanation: SEM scans the specimen surface with an electron beam
and produces a 3D-like image of the surface.
Page 2 of 57
, MCB 252 Cell Biology
5. Differential centrifugation separates cell components mainly according to
their:
A. Hydrophobicity
B. Size and density
C. Charge
D. Amino acid sequence
ANSWER : B. Size and density
Explanation: Larger and denser particles sediment at lower speeds, so
organelles pellet in a predictable order.
6. Which cell component is usually found in the pellet after the first, low-
speed spin of a homogenate?
A. Microsomes
B. Soluble enzymes
C. Nuclei and unbroken cells
D. Ribosomes
ANSWER : C. Nuclei and unbroken cells
Explanation: Nuclei and unbroken cells are the heaviest components
and pellet first.
7. Equilibrium density-gradient centrifugation separates particles on the
basis of:
A. Buoyant density
B. Isoelectric point
C. Binding affinity
D. Molecular weight only
ANSWER : A. Buoyant density
Explanation: Particles migrate until they reach the point in the
gradient equal to their own buoyant density.
Page 3 of 57
, MCB 252 Cell Biology
8. Western blotting is used to detect:
A. Specific RNA molecules
B. Specific proteins using antibodies
C. Specific DNA sequences
D. Lipids in membranes
ANSWER : B. Specific proteins using antibodies
Explanation: Proteins are separated by gel electrophoresis, transferred
to a membrane and detected with specific antibodies.
9. The main advantage of confocal microscopy is that it:
A. Magnifies more than an electron microscope
B. Works only on dead cells
C. Removes out-of-focus light to give optical sections
D. Requires no fluorescent labels
ANSWER : C. Removes out-of-focus light to give optical sections
Explanation: A pinhole blocks out-of-focus light, giving sharp optical
sections of thick specimens.
10. Which statement is a principle of the cell theory attributed to Virchow?
A. All cells contain a nucleus
B. All cells arise from pre-existing cells
C. Cells can arise by spontaneous generation
D. Viruses are the smallest cells
ANSWER : B. All cells arise from pre-existing cells
Explanation: Virchow's contribution was the statement that every cell
comes from a pre-existing cell.
11. The defining feature of a prokaryotic cell is the absence of:
A. A cell wall
B. Ribosomes
C. A plasma membrane
D. A membrane-bound nucleus
ANSWER : D. A membrane-bound nucleus
Explanation: Prokaryotes lack a nucleus enclosed by a nuclear
envelope; their DNA lies in the nucleoid.
Page 4 of 57
