Question

Some antifungal medications work by blocking DNA synthesis in the fungal cell. Describe where in the cell cycle such a medication would halt the fungal cell and the consequences of this early termination of the cycle.

Answer 1

The cell cycle is broadly divided into two phases - Interphase, and Mitotic phase

Interphase is the phase where the DNA replication and Protein synthesis take place.

Mitotic phase is the phase where one cell divides into two,and the molecules synthesized in the Interphase are divided equally to the daughter cells.

Now, when it comes to Interphase, it is further sub-divided into three phases - G1 phase, S phase, and G2 phase. G1 phase is the time in which the cell makes more proteins and becomes larger in size. The DNA replicates in the S phase. During G2 phase, the cell becomes ready to exit Interphase, and enter mitotic phase.

In case of antifungals affecting DNA synthesis, the S-Phase is affected. Since replication of DNA is hindered, the fungal cell cannot propagate further, and eventually dies out (owing to early termination of Interphase).