Cell Bio Final Exam Multiple Choice 2
Questions with Complete Answers
Which of the following organelles is essentially equal in structure to basal bodies?
centrioles
lysosomes
peroxisomes
intermediate filaments - ANSWER-centrioles
MTOCs control which of the following activities?
a. They control the number of microtubules that form.
b. They control the polarity of the microtubules that form.
c. They control the number of protofilaments that make up the microtubule walls.
d. They control the time and location of microtubule assembly.
e. all of the above - ANSWER-e
What evidence suggests the presence of gamma-tubulin in all MTOCs?
a. Fluorescent anti- gamma -tubulin antibodies stain all types of MTOCs.
b. If antibodies against gamma -tubulin are injected into a living cell, microtubule
reassembly after drug- or cold induced depolymerization is blocked.
c. Genetically engineered fungi lacking a functional gamma -tubulin gene cannot
assemble normal microtubules.
d. If antibodies against gamma -tubulin are injected into a living cell, microtubule
reassembly after drug- or cold induced depolymerization is blocked.
e. a, b and c - ANSWER-a
Centrosomes were purified and incubated with gold-labeled anti- -tubulin antibodies.
What observation was made after this treatment?
a. Rectangular assemblies of gold particles were seen at the minus ends of
microtubules.
b. Circular clusters of gold were seen at the minus ends of microtubules.
c. Semi-circular clusters of gold were seen at the minus ends of microtubules.
d. Circular and semi-circular clusters of microtubules were seen at the plus ends of
microtubules.
e. b and c - ANSWER-b
Ring-shaped structures have been isolated from cell extracts. They have been
shown to nucleate microtubule assembly in vitro. What are these ring-shaped
complexes called?
turks
gamma -TuRCs
ring turcs
gamma structures - ANSWER-gamma-TuRCs and gamma structures
, Which of the following microtubules are the most labile (or sensitive to disassembly)?
spindle microtubules
cytoskeleton microtubules
mature neuronal microtubules
microtubules of cilia
a and b - ANSWER-spindle and cytoskeleton
Which of the following microtubules are the most stable (or least sensitive to
disassembly)?
spindle microtubules
centriolar microtubules
mature neuronal microtubules
microtubules of cilia
b and d - ANSWER-cilia
What is the mechanism by which taxol and drugs similar to it disrupt the dynamic
activity of microtubules?
a. They rapidly disassemble microtubules.
b. They inhibit the disassembly of microtubules.
c. They stabilize microtubules in the polymerized state.
d. They cause microtubules to undergo contraction.
e. b and c - ANSWER-b
Why are taxol, vinblastine and other drugs like them used as chemotherapy agents?
a. They preferentially kill tumor cells.
b. They preferentially stabilize tumor cells.
c. They disrupt tumor cell membranes.
d. They prevent entry of cells into the stage of meiosis.
e. They inhibit mitochondria. - ANSWER-a
Taxol inhibits the disassembly of microtubules. How does this harm the cells?
a. It inhibits mitochondrial function.
b. It inhibits lysosomal function.
c. The cell cannot assemble new and needed structures containing microtubules.
d. Microtubules cannot contract fully as they could before the application of the drug.
e. c and d - ANSWER-e
Why do tumor cells die after exposure to drugs that either disrupt or stabilize the
structure of microtubules?
a. Mitosis is stopped in the presence of the drugs.
b. The tumor cells attempt to complete cell division in the absence of a functional
spindle, killing the cells.
c. There is a checkpoint that prevents the entry into mitosis.
d. The drugs cause the disintegration of the tumor cell membranes.
e. a and c - ANSWER-b
Which of the following is a mechanism by which microtubular spatial organization
can be changed?
a. rearrangement of existing microtubules
Questions with Complete Answers
Which of the following organelles is essentially equal in structure to basal bodies?
centrioles
lysosomes
peroxisomes
intermediate filaments - ANSWER-centrioles
MTOCs control which of the following activities?
a. They control the number of microtubules that form.
b. They control the polarity of the microtubules that form.
c. They control the number of protofilaments that make up the microtubule walls.
d. They control the time and location of microtubule assembly.
e. all of the above - ANSWER-e
What evidence suggests the presence of gamma-tubulin in all MTOCs?
a. Fluorescent anti- gamma -tubulin antibodies stain all types of MTOCs.
b. If antibodies against gamma -tubulin are injected into a living cell, microtubule
reassembly after drug- or cold induced depolymerization is blocked.
c. Genetically engineered fungi lacking a functional gamma -tubulin gene cannot
assemble normal microtubules.
d. If antibodies against gamma -tubulin are injected into a living cell, microtubule
reassembly after drug- or cold induced depolymerization is blocked.
e. a, b and c - ANSWER-a
Centrosomes were purified and incubated with gold-labeled anti- -tubulin antibodies.
What observation was made after this treatment?
a. Rectangular assemblies of gold particles were seen at the minus ends of
microtubules.
b. Circular clusters of gold were seen at the minus ends of microtubules.
c. Semi-circular clusters of gold were seen at the minus ends of microtubules.
d. Circular and semi-circular clusters of microtubules were seen at the plus ends of
microtubules.
e. b and c - ANSWER-b
Ring-shaped structures have been isolated from cell extracts. They have been
shown to nucleate microtubule assembly in vitro. What are these ring-shaped
complexes called?
turks
gamma -TuRCs
ring turcs
gamma structures - ANSWER-gamma-TuRCs and gamma structures
, Which of the following microtubules are the most labile (or sensitive to disassembly)?
spindle microtubules
cytoskeleton microtubules
mature neuronal microtubules
microtubules of cilia
a and b - ANSWER-spindle and cytoskeleton
Which of the following microtubules are the most stable (or least sensitive to
disassembly)?
spindle microtubules
centriolar microtubules
mature neuronal microtubules
microtubules of cilia
b and d - ANSWER-cilia
What is the mechanism by which taxol and drugs similar to it disrupt the dynamic
activity of microtubules?
a. They rapidly disassemble microtubules.
b. They inhibit the disassembly of microtubules.
c. They stabilize microtubules in the polymerized state.
d. They cause microtubules to undergo contraction.
e. b and c - ANSWER-b
Why are taxol, vinblastine and other drugs like them used as chemotherapy agents?
a. They preferentially kill tumor cells.
b. They preferentially stabilize tumor cells.
c. They disrupt tumor cell membranes.
d. They prevent entry of cells into the stage of meiosis.
e. They inhibit mitochondria. - ANSWER-a
Taxol inhibits the disassembly of microtubules. How does this harm the cells?
a. It inhibits mitochondrial function.
b. It inhibits lysosomal function.
c. The cell cannot assemble new and needed structures containing microtubules.
d. Microtubules cannot contract fully as they could before the application of the drug.
e. c and d - ANSWER-e
Why do tumor cells die after exposure to drugs that either disrupt or stabilize the
structure of microtubules?
a. Mitosis is stopped in the presence of the drugs.
b. The tumor cells attempt to complete cell division in the absence of a functional
spindle, killing the cells.
c. There is a checkpoint that prevents the entry into mitosis.
d. The drugs cause the disintegration of the tumor cell membranes.
e. a and c - ANSWER-b
Which of the following is a mechanism by which microtubular spatial organization
can be changed?
a. rearrangement of existing microtubules
