A cell has a loss-of-function mutation in one of the MCM proteins. Which of the following is a likely phenotype for this cell? Why?

a. A longer S-phase compared to a wildtype cells
b. A shorter S-phase compared to wildtype cells
c. A missing S-phase in the cell cycle
d. A S-phase the same length as wildtype cells.

Option b. A shorter S-phase compared to wildtype cells

Explanation:

A gene mutation affects the sequence of the bases in the DNA double helix. This results in the coding for a wrong amino acid. The coding error, in turn, means  that there will be an error in the protein chain. Not only that, there would be a disruption in the cell-division in the process. For instance, the different phases of cellular division would be impacted. Some will be longer, shorter, or dormant after some period of time. In this mutation, the S phase will be shortened compared to the cells of the same group and genre.