As cells increase in size, their volume increases more rapidly than their surface area. Small cells...
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Transcript of As cells increase in size, their volume increases more rapidly than their surface area. Small cells...
Why are cells so small??
As cells increase in size, their volume increases more rapidly than their surface area.
Small cells have a large Surface area to volume ratio (large surface area relative to a small volume)
The Size Of Cells.
This means that more of the surface of the cell is in contact with it’s surroundings.
This allows for a greater rate of diffusion of gases and nutrients in and out of the cell
What Is The Advantage Of Having A Large SA:Volume ratio?
In a cube with sides of 1cm, each face has an area of 1cm x 1cm = 1cm2
Since the cube has 6 faces, the total surface area is 6cm2
The volume of the cube is 1x1x1=1cm3
The surface area:volume ratio is 6:1 S:A Volume
Prove It!
A cube with sides of 2cm will have a surface area of 2x2x6=24cm2
And a volume of 2x2x2=8cm3
The surface area to volume ratio 24:8 = 3:1S.A. Volume
Prove It!
So as the cube increases in size, the SA:Volume ratio decreases.
Therefore as a cell increases in size, its ability to diffuse nutrients in and wastes out will decrease.
This is why cells are small
Conclusion