Why do cells increase in number and not in size?

The volume of a cell grows faster than its surface area; this leads to metabolic processes such as moving materials in and out of the cell becoming much more difficult. To prevent this, cells proliferate in order to maintain a healthy ratio of volume to SA.

Increasing in size would require a greater demand for resources and energy, making it less efficient than increasing in number. Larger cells may also have trouble efficiently transporting nutrients and waste, whereas smaller cells have a higher surface area-to-volume ratio, allowing for more efficient exchange of materials. Cell division is the process by which cells multiply in order to support growth, repair, and reproduction.

Cells increase in number rather than in size primarily due to the limitations imposed by their surface area-to-volume ratio. As cells grow larger, their volume increases at a faster rate than their surface area. This means that the cell's ability to exchange nutrients, gases, and waste products across its membrane becomes less efficient as it grows larger. Eventually, the cell would struggle to adequately supply its interior with essential molecules and remove waste efficiently.

By increasing in number through processes like cell division (such as mitosis in eukaryotic cells), cells can maintain a more favorable surface area-to-volume ratio. This allows for more efficient exchange of substances across the cell membrane, ensuring that the needs of the cell are met and waste products are removed effectively. Additionally, by dividing into multiple smaller cells, organisms can also increase their overall surface area, which is beneficial for functions like absorption and secretion.

Overall, cells increase in number rather than in size to maintain optimal conditions for cellular activities and to ensure efficient exchange of substances with their environment.