1. Cell Size Surface area : Volume
Page 47 & 48 in your ISN

2. Cell Size Limits Are whale cells the same size as star fish cells?
Yes!

3. Which cell is best at diffusion?
Diffusion – movement of particles from a high concentration to low concentration
Diffusion is not very efficient in large cells
Diffusion works BEST when cells are small
Activity from Unit 3 – Diffusion of “nutrients” – Smaller cubes are better at diffusion because they have a greater surface area to volume ratio

4. Why are cells so small? More efficient at getting things into the cell
Nutrients
Water
Oxygen
Remove things from the cell faster
Waste
DNA limits cell size
If cell is too big then DNA cannot make enough proteins to support the cell

5. What limits the size of cells?
Surface Area to Volume Ratio -
How much space is on the outside (cell membrane) compared to the space on the inside of the cell.
-As the surface area of something increases, it’s volume increases faster
Surface area = L x W x # of sides (cm2) the surface of an object. The outside covering of a cell. (cell membrane)
Volume = L x W x H (cm3) The space inside the cell
A small object has a high surface area to volume ratio ex: 6/1
A large object has a small surface area to volume ratio ex: 24/8

6. It takes more time for the nutrients to reach the center of this cell
Large Cell
It takes more time for the nutrients to reach the center of this cell

7. Smaller cell
It takes less time for the same nutrients to reach the center of this cell

8. Which cell has the greatest surface area to volume?
Has the greatest surface area due to the microvilli

9. Which shape has the greatest surface area : volume ratio?
Sphere
Cube
Hollow tube
SA:V : : :1

10. Answers Not enough nutrients coming in fast enough
As a cell gets larger which increases at a faster rate, the surface area or the volume?
Volume
If a cell were larger, would it’s interior structures be closer or further from the cell membrane?
Further
What problems might occur if cells were too large?
Not enough nutrients coming in fast enough

11. Conclusion
As cell size increases, the surface area to volume ratio Decreases (small surface area to volume ratio), which can lead to death of a cell.
Having a large surface area to volume ratio is important to the functioning of cells since it gets materials, nutrients, oxygen, & wastes into & out of it faster.
Cells divide before they get too big!

12. Define Vocab Term pg. 44
Surface-Area: Volume Ratio