MCB 150 FINAL EXAM QUESTIONS
|LATEST VERSION 2025\26 |
UPDATED NOTES |GUARANTEED
ACCURATE ANSWERS
Which of the following drugs works by stabilizing microtubules rather
than blocking their formation?
A. Taxol
B. Vinblastine
C. Colchicine
D. Vincristine
E. Colcemid - ACCURATE ANSWERS✔✔ A. Taxol
Which one of the following statements about microtubules is correct?
A. Tubulin dimers with nucleoside diphosphates in their nucleotide
binding site(s) have a lower affinity for each other than tubulin dimers
with nucleoside triphosphates in their nucleotide binding site(s).
B. In vivo, polymerization of microtubules typically occurs at the minus
end because the plus end is anchored.
C. Myosin is a motor protein that moves toward the plus end of
microtubules.
D. Only the alpha subunit of a tubulin dimer has a nucleotide binding
site.
,E. ATP is the nucleotide that occupies the nucleotide binding site(s) of
tubulin dimers. - ACCURATE ANSWERS✔✔ A. Tubulin dimers with
nucleoside diphosphates in their nucleotide binding site(s) have a lower
affinity for each other than tubulin dimers with nucleoside triphosphates
in their nucleotide binding site(s).
Which of the following is a property of microtubules, but not of actin?
A. In vitro, both ends can show dynamic growth
B. Can be used for vesicle transport
C. Subunits are dimeric
D. Can form stable arrangements to support cell projections
E. Polarity at filament ends - ACCURATE ANSWERS✔✔ C. Subunits
are dimeric.
Microtubule subunits (tubulin) are dimeric, while actin filament subunits
(G-actin) are monomeric.
Identify if the following statements regarding microtubule function in a
cell are true or false.
Choices: True, False.
1. Microtubules are completely unchanging, stable structures.
2. Cilia are extensions of cytoplasm stabilized by microtubules.
3. During interphase, microtubules typically do not reach the cell
membrane.
4. Microvilli are the same as flagella. - ACCURATE ANSWERS✔✔ 1.
False
,2. True
3. True
4. False
Decide if the following statements are true or false.
Choices: True, False.
1. Tubulin subunits have ATP-binding sites.
2. Colcemid could be used as a muscle relaxant; it would relieve tension
by promoting the degradation of actin filaments.
3. In vivo, microtubules often have their plus end anchored into the
MOC.
4. Vinblastin would be likely to affect a human embryo more severely
than a grown person. - ACCURATE ANSWERS✔✔ 1. False. Tubulin
subunits have GTP-binding sites.
2. False. Colcemid could be used in the lab to induce depolymerization
of microtubules and non-specifically affects all microtubules.
3. False. In vivo, microtubules have their minus ends anchored into the
MTOC.
4. True. Vinblastin induces depolymerization of microtubules and targets
rapidly-dividing cells.
Treatment of a cell with the drug Colchicine will:
A. promote microtubule depolymerization because the
colchicine will bind the microtubule ends.
, B. stabilize microtubule length because colchicine will bind the
microtubule ends.
C. promote microtubule depolymerization because the effective
concentration of tubulin will be too low to sustain polymerization.
D. stop microtubule depolymerization because the free tubulin will bind
the colchicine.
E. promote microtubule polymerization because the colchicine will bind
the microtubule ends. - ACCURATE ANSWERS✔✔ C. promote
microtubule depolymerization because the effective concentration of
tubulin will be too low to sustain polymerization.
Identify if each of the following statements are true or false.
Choices: True, False.
1. Microtubules and tubulin building blocks both have polarity.
2. If the concentration of GTP-bound tubulin is increased,
depolymerization is more likely to occur.
3. The addition of ATP to tubulin will increase the concentration of ATP
bound tubulin and the microtubule will polymerize.
4. Assembly and disassembly of microtubules is typically fastest at the
plus end in a living cell. - ACCURATE ANSWERS✔✔ 1. True.
2. False. If the concentration of GTP-bound tubulin is increased,
polymerization is more likely to occur.
3. False. The addition of GTP to tubulin will increase the concentration
of GTP-bound tubulin and the microtubule will polymerize.
4. True. (since the minus end is bound to the MTOC)
|LATEST VERSION 2025\26 |
UPDATED NOTES |GUARANTEED
ACCURATE ANSWERS
Which of the following drugs works by stabilizing microtubules rather
than blocking their formation?
A. Taxol
B. Vinblastine
C. Colchicine
D. Vincristine
E. Colcemid - ACCURATE ANSWERS✔✔ A. Taxol
Which one of the following statements about microtubules is correct?
A. Tubulin dimers with nucleoside diphosphates in their nucleotide
binding site(s) have a lower affinity for each other than tubulin dimers
with nucleoside triphosphates in their nucleotide binding site(s).
B. In vivo, polymerization of microtubules typically occurs at the minus
end because the plus end is anchored.
C. Myosin is a motor protein that moves toward the plus end of
microtubules.
D. Only the alpha subunit of a tubulin dimer has a nucleotide binding
site.
,E. ATP is the nucleotide that occupies the nucleotide binding site(s) of
tubulin dimers. - ACCURATE ANSWERS✔✔ A. Tubulin dimers with
nucleoside diphosphates in their nucleotide binding site(s) have a lower
affinity for each other than tubulin dimers with nucleoside triphosphates
in their nucleotide binding site(s).
Which of the following is a property of microtubules, but not of actin?
A. In vitro, both ends can show dynamic growth
B. Can be used for vesicle transport
C. Subunits are dimeric
D. Can form stable arrangements to support cell projections
E. Polarity at filament ends - ACCURATE ANSWERS✔✔ C. Subunits
are dimeric.
Microtubule subunits (tubulin) are dimeric, while actin filament subunits
(G-actin) are monomeric.
Identify if the following statements regarding microtubule function in a
cell are true or false.
Choices: True, False.
1. Microtubules are completely unchanging, stable structures.
2. Cilia are extensions of cytoplasm stabilized by microtubules.
3. During interphase, microtubules typically do not reach the cell
membrane.
4. Microvilli are the same as flagella. - ACCURATE ANSWERS✔✔ 1.
False
,2. True
3. True
4. False
Decide if the following statements are true or false.
Choices: True, False.
1. Tubulin subunits have ATP-binding sites.
2. Colcemid could be used as a muscle relaxant; it would relieve tension
by promoting the degradation of actin filaments.
3. In vivo, microtubules often have their plus end anchored into the
MOC.
4. Vinblastin would be likely to affect a human embryo more severely
than a grown person. - ACCURATE ANSWERS✔✔ 1. False. Tubulin
subunits have GTP-binding sites.
2. False. Colcemid could be used in the lab to induce depolymerization
of microtubules and non-specifically affects all microtubules.
3. False. In vivo, microtubules have their minus ends anchored into the
MTOC.
4. True. Vinblastin induces depolymerization of microtubules and targets
rapidly-dividing cells.
Treatment of a cell with the drug Colchicine will:
A. promote microtubule depolymerization because the
colchicine will bind the microtubule ends.
, B. stabilize microtubule length because colchicine will bind the
microtubule ends.
C. promote microtubule depolymerization because the effective
concentration of tubulin will be too low to sustain polymerization.
D. stop microtubule depolymerization because the free tubulin will bind
the colchicine.
E. promote microtubule polymerization because the colchicine will bind
the microtubule ends. - ACCURATE ANSWERS✔✔ C. promote
microtubule depolymerization because the effective concentration of
tubulin will be too low to sustain polymerization.
Identify if each of the following statements are true or false.
Choices: True, False.
1. Microtubules and tubulin building blocks both have polarity.
2. If the concentration of GTP-bound tubulin is increased,
depolymerization is more likely to occur.
3. The addition of ATP to tubulin will increase the concentration of ATP
bound tubulin and the microtubule will polymerize.
4. Assembly and disassembly of microtubules is typically fastest at the
plus end in a living cell. - ACCURATE ANSWERS✔✔ 1. True.
2. False. If the concentration of GTP-bound tubulin is increased,
polymerization is more likely to occur.
3. False. The addition of GTP to tubulin will increase the concentration
of GTP-bound tubulin and the microtubule will polymerize.
4. True. (since the minus end is bound to the MTOC)
