1. Cell Size and Function
Biology 11
CHS

2. Why are cells so small?
To carry out their work, cells need a constant supply of materials:
oxygen, water and food particles.
They need to get rid of waste products

3. How do materials get in and out of the cell?
The cell membrane!

4. To have an idea of the problem imagine ….
A cell as a swimming pool with a diameter of 50 m.
You need to swim to the center with a beach ball (food), and swim back carrying a lifebuoy (waste) 12 times in a certain time period to keep the cell alive!

5. Imagine a pool that is 100 m instead of 50m!

6. Volume and surface area
The volume of any object is the amount of space it takes up.
The surface area of an object is the area of the surface that encloses it.
What covers the surface area of a cell?

7. Surface area-to-volume ratio
The relationship between volume and surface area changes as the object gets bigger or smaller.
This is known as surface area-to-volume ratio

8. Observations
Surface area and Volume both increase as you add more cells or as the cells grow
The ratio of SA to V changes
The volume increases faster than the surface area

9. Structural Adaptations
A structural adaptation to increase surface area to volume ratio is to be rectangular prism and very flat (almost two dimension).
A second structural adaptation to increase surface area is folding as seen in …

10. Conclusion
The surface area in any cell is the cell membrane. The volume is everything contained in the cytoplasm.
Every cell to survive must get raw materials in such as protein, Oxygen, and glucose.
Cells must also continually get rid of waste such as CO2, ammonia, salts.

11. Conclusion The only way to get materials in and out of the cell….
As a cell grows it requires a greater amount of material however there is less surface area compared to its volume to allow materials in and out of the cell membrane.

12. Calculating Volume Volume = height X width X length
Example  4 cm X 4 cm X 4 cm = 64 cm3

13. Calculating surface area
Surface area of a cube = calculate the area of one side by multiplying width X height and then multiply by 6 (the cube has 6 sides).
Example  : 4cm X 4cm X 6 sides = 96cm2

14. Surface Area and Volume of a Rectangle