Cells are limited in size by the?

What do you think is the answer? What makes the outline of cells? :rolleyes:

Cells are limited in size by the exchange of materials through the cell membrane. The larger the cell, the smaller the membrane is in proportion to the cytoplasm. Most cells are quite small, so they have a big surface area for their size.

Egg cells are the BIG exception, but they have a special way of dealing with waste materials and "breathing" for lack of a better word ("gas exchange").

The largest cell today is an ostrich egg. I'm sure dinosaurs had bigger egg cells though.

The limits on cell size:
1. Surface to volume ratio- if cells become too big, their volume becomes too large and they can't be serviced by their surface area.
2. The rates at which some molecules move (in the cell)- cells should be kept smaller so if molecules are moving, they can get from one end of the cell to the other, at a reasonable rate.
3. To maintain concentrations- if the volume of the cell is too great, more energy would be required to maintain concentrations inside the cell.

Many algae are huge single cell organisms. THe cell wall is the boundary and the genes are the limiting factor

Good answers. Of course the question is more than two years old. :)

Whoa! My bad. When I looked at the date I thought it said 2007!