Question

Taxol was an important new chemotherapy drug because it

A) was present in only very low amounts in tree bark.
B) killed ovarian and breast cancer cells.
C) targeted a different step of the cell cycle compared to other drugs.
D) could be extracted from widely available trees.
E) was effective and inexpensive.

Answer 1

Taxol was significant because it targeted a unique phase in the cell cycle, stabilizing microtubules to disrupt cell division, unlike other chemotherapy drugs that inhibit DNA replication.

Step-by-step explanation:

Taxol, also known as Paclitaxel, was an important new chemotherapy drug because it targeted a different step of the cell cycle compared to other drugs. Specifically, Taxol disrupts the equilibrium between free tubulin and microtubules by shifting it in the direction of assembly, thereby stabilizing microtubules and forming abnormal bundles that disrupt mitosis. Unlike other chemotherapy drugs that might inhibit S phase replication, Taxol actually blocks spindle fiber microtubules from depolymerizing, which in turn blocks mitotic anaphase and telophase, key phases in cell division. Additionally, the synthesis of Taxol in the laboratory is complicated and inefficient, which unfortunately contributes to its costliness and limited availability.