Increasing the size of the cube-shaped cell increases the volume. However, the surface area-to-volume ratio decreases. This means that the simple diffusion would take more time distribute nutrients across the cell (and even in the eliminate waste). It would need bulk transport such as vesicle transport, otherwise cell activities would slow down.
The cell structures that best reveal evolutionary unity is the Plasma Membrane and DNA, which are the best cellular structures to study evolutionary unity.
