Name _________________________________________________________________________________ Date____________ Period__________
Why Are Cells So Small?
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? In this lab, you will measure how much greater the increase in volume and surface area is an object grows.
Prelab:
→ SURFACE AREA = __________________________________________________________________________________________________
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→ VOLUME = ________________________________________________________________________________________________________
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1.
Anything that a cell takes in, like oxygen and food, or lets out, such as carbon dioxide, must go through the cell membrane. Which measurement
of the cells best represents how much cell membrane the models have? _______________________________________________________
2.
The cell contents, nucleus and cytoplasm, use the oxygen and food while producing wastes. Which measurement best represents the cell
content? __________________________________________________________________________________________________________
Procedure:
1.
Complete the table and graph for # 7 on the back of this paper.
2.
Working together, assemble your 1 cm cubes to form a cube as large as your 2 cm cube.
a.
How many 1 cm cubes were needed to make a 2 cm cube? __________________________________________________________
b.
Using your calculations from above, compare the surface area amounts of the assembled cubes have separately versus assembled.
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Analysis:
3.
Looking at the graph, which increases faster – surface area or volume? _________________________________________________________
4.
Using your answers from questions 1 & 2 in the prelab, what do you think the significance of the graph shows about cell size compared to
movement of materials into and out of the cell? ____________________________________________________________________________
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5.
Most cells and microorganisms measure less that 0.01 cm on a side. Explain why large organisms have developed from MORE cells rather than
LARGER cells. _____________________________________________________________________________________________________
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6.
Using your textbook to help, give two reasons why cells divide.
a.
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b.
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7.
Calculate the surface area and volume for each of the listed cubes.
Cube Size
Surface Area (cm2)
Volume (cm3)
(length X width X number of sides)
(length X width X height)
0.01 cm
1 cm
2 cm
4 cm
8 cm
→ Make a line graph for the surface area AND volume of the 1 cm, 2 cm, 4 cm, and 8 cm cubes. Use one line for the area of the cubes and a
second line for the volume of the cubes.