Why are cells so small?
Living cells are constantly exchanging substances with their surroundings.
Cells have to absorb nutrients and get waste products out.
Most cells, including our body, need to absorb oxygen to get energy.
What if the cells are large?
Just as large chunks of salt are harder to dissolve than small ones. Large cells become harder to absorb as much material as they want.
A cellular mass exchange takes place through the cell membrane because the cell membrane is not wide enough.
Most cells are small. (Plant stem cells)
The reason why orange flesh cells are huge is that there is little need for material exchange.
Eggs are also one cell. Eggs, like oranges, rarely exchange substances with the outside, so it is not a problem even if the cells are large.