MCB 150 FINAL EXAM NEWEST 2025

• | Page

MCB 150 FINAL EXAM NEWEST 2025

FEATURING 400 ACCURA TE AND

VERIFIED QUESTIONS COVERING

MOLECULAR AND CELLUL AR

BIOLOGY, INCLUDING D NA

REPLICATION, TRANSCRIPTION,

TRANSLATION, CELL ST RUCTURE,

AND GENE REGULATION

Question :Which of the following drugs works by

stabilizing microtubules rather than blocking their formation?

• Taxol
• Vinblastine
• Colchicine
• Vincristine
• Colcemid

Correct answer:A. Taxol

• | Page

Question :Which one of the following statements about

microtubules is correct?

• 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).

• In vivo, polymerization of microtubules typically

occurs at the minus end because the plus end is anchored.

• Myosin is a motor protein that moves toward the plus

end of microtubules.

• Only the alpha subunit of a tubulin dimer has a

nucleotide binding site.

• ATP is the nucleotide that occupies the nucleotide

binding site(s) of tubulin dimers.

Correct answer: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).

• | Page

Question :Which of the following is a property of

microtubules, but not of actin?

• In vitro, both ends can show dynamic growth
• Can be used for vesicle transport
• Subunits are dimeric
• Can form stable arrangements to support cell

projections

• Polarity at filament ends

Correct answer:C. Subunits are dimeric. Microtubule

subunits (tubulin) are dimeric, while actin filament subunits (G-actin) are monomeric.

Question :Treatment of a cell with the drug Colchicine

will:

• promote microtubule depolymerization because the

colchicine will bind the microtubule ends.

• stabilize microtubule length because colchicine will

bind the microtubule ends.

• | Page

• promote microtubule depolymerization because the

effective concentration of tubulin will be too low to sustain polymerization.

• stop microtubule depolymerization because the free

tubulin will bind the colchicine.

• promote microtubule polymerization because the

colchicine will bind the microtubule ends.

Correct answer:C. promote microtubule depolymerization

because the effective concentration of tubulin will be too low to sustain polymerization.

Question :Which of the following statements is TRUE?

• Axons and dendrites are examples of microvilli.
• Axons and dendrites are important for the motility of

nerve cells.

• Microtubules are found in a 9+2 pattern in axons but

not dendrites.

• Axons and dendrites are anchored in the centrosome of

nerve cells.

• Axons and dendrites are the cytoplasmic extensions of

nerve cells.