Obviously its surface area gets bigger, but the real issue is that its surface area gets bigger at a slower rate than its volume. In other words, the surface area to volume ratio decreases, so before long there is not enough surface area to take in enough nutrients to feed the greater volume. This is the principle limiting factor in how large cells can grow. if the cell is getting bigger as a result of being placed in a hypotonic solution. That situation could end in the cell bursting (blowing up). However, the question sounds like it is asking about getting bigger through normal cell growth. hope it helped you. :)
