Download MODELING LIMITS TO CELL SIZE

MODELING LIMITS TO CELL SIZE
Introduction
Why can’t cells continue to grow larger and larger to become giant cells, like a blob? Why are
most cells, whether from an elephant or an earthworm microscopic in size? What happens
when a cell grows larger and what causes it to divide into smaller cells rather than growing
infinitely larger? This investigation will simulate the changing relationship of Surface Area to
Volume for a growing cell. You will see how the changing relationship between surface area and
volume limits the size of cells.
Background
The four paper models represent cube-shaped cells at increasing stages of growth. The goal of
the day is to discover how the relationship between surface area and volume changes as the
“cells” become larger.
Procedures
1. Use your math skills to develop an equation that would compute the following data
about the cell models.
a. Area of one face _____________________________
b. Total surface area of the cell _____________________________
c. Volume of the cell ______________________________
2. Use your equations to calculate the answers for the questions above for each box.
Record your answers in data table 1.
3. Calculate the surface area : volume ratios for each cell. Remember to divide the surface
area by the volume to get a X:1 ratio.
Data:
Data Table 1 : Measurements of Cell Models
Cell
A
B
C
D
Area of one face
Total Surface Area
Calculated Volume
Data Table 2: Surface Area to Volume Ratios
Cell
Total Surface Area to Volume Ratio
A
B
C
D
Analysis Questions
1. Which measurement of the cell best represents how much cell membrane the models
have?
2. Which measurement best represents the cell content?
3. As the cell grows larger, will it need more or less cell membrane to survive?
4. As the cell grows larger, does the surface area to volume ratio get larger, smaller, or
remain the same?
5. Why can’t cells survive when the total surface area to volume ratio becomes too small?
6. Which size cell has the greatest total surface area to volume ratio?
7. Which cell has the greatest chance of survival?
8. What can cells do to increase their total surface area to volume ratio?