Cells are small because as they get larger, their volume increases faster than their surface area. This decreases the surface area to volume ratio, making it difficult for cells to efficiently exchange gases, nutrients, and wastes through their cell membranes. Maintaining a high surface area to volume ratio allows cells to effectively transport materials needed for survival.

1. Notes: Cell Size (pg 2)

2. Notes: Cell Size (pg 2)
• Why are cells so small?

3. Notes: Cell Size (pg 2)
• Why are cells so small?
• Almost all cells are microscopic

4. Surface Area to Volume Ratio
• Cells must constantly exchange ions, gases,
nutrients, and wastes with their environment

5. Surface Area to Volume Ratio
• Cells must constantly exchange ions, gases,
nutrients, and wastes with their environment
• This occurs through the cell membrane

6. Surface Area to Volume Ratio
• Cells must constantly exchange ions, gases,
nutrients, and wastes with their environment
• This occurs through the cell membrane
• As cells get larger, the volume increases faster
than the surface area

7. Surface Area to Volume Ratio
• Cells must constantly exchange ions, gases,
nutrients, and wastes with their environment
• This occurs through the cell membrane
• As cells get larger, the volume increases faster
than the surface area
• If the SA:V ratio gets too low, the cell can’t
exchange materials efficiently and it will die