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# Biology/cell

Question
Why are most cells small?

THis involves a little math and the cell metabolism. Cell must exchange gases and nutrients across the cell membrane in order to carry out all activities. There is a principla called the scale effect taht states that as a cell increases in size there is a decrease in the surface area to volume ratio
Comsider a cube of
1mm
Surface Area = 1x1x6 or 6 sq mm
Volume  1 x 1 x 1 = 1 cubic mm  SA-Vol ratio = 6-1
Now double the cube size to
2mm
Surface area = 2 x 2 x 6  =24 sq mm
Vol = 2 x 2 x 2 =8 cublc mm   SA -vol ratio 3-1
The metabolic needs of the cell have doubled while thw surface area the materials must pass through is 50 % less.
How does the cell respond ? It divides

Biology

Volunteer

#### Walter Hintz

##### Expertise

Science teacher for over 50 years. MSc. in biology. I can answer questions in general biology, zoology, botany, anatomy and physiology and biochemistry.

##### Experience

I have a MSc in biology and have been a science teacher for over 50 years. At present I am a faculty member at a college and a science consultant at seven catholic schools.

Publications
The Ohio journal of Science
Momentum-The Journal of the Catholic Education Association