LAB 22 Cell Size Surface Area to Volume and Diffusion
Materials:
Metric ruler, razor blades, potato pieces, paper towels, iodine
Purpose:
to identify why cells are so small.
Hypothesis:
Make a statement as to which potato cubes will diffuse the closer to the center of a cell (small, medium, large.
__________________________________________________________________________________________________________________________________________________________________________
Dimensions For Experiment
3 Cubes with sizes
A) 0.5 cm
B) 1.0 cm
C) 2.0 cm
Experimental Evidence:
1. Using a razor blade and paper towels, carefully cut 3 potato cubes using the dimensions from above.
2. Obtain TEACHER’S SIGN-OFF BEFORE you proceed!
3. Submerge the potato cubes (cells) into the iodine solution for 20 minutes.
4. While you are waiting for 10 minutes, calculate the surface area, volume, and surface area to volume ratio for each of the 3 potato cubes (cells).
AFTER 10 Minutes
5. Carefully remove the potato cubes (cells) from the iodine solution and place them on absorbent paper towels.
6. Cut each cell in half and observe the inside.
7. Draw each cell in detail showing the pattern of iodine throughout the potato.
Conclusion Questions: Use complete sentences.
1. What does the iodine used in the lab represent in the cell?
2. As the size of the cell increases, which increases faster: cell surface area or cell volume?
3. As cell size increases, what happens to the surface area to volume ratio? Give examples from the lab.
4. According to your drawings, in which cell (potato) did the iodine diffuse all the way to the center of the cube? Discuss the differences between the cells
5. Based on your understanding of cell size and the rate (speed) of diffusion,explain why there are NO GIANT CELLS! Discuss diffusion in your answer.
Conclusion:
Restate your Hypothesis and state whether or not if it is correct and why. Refer to your data and give numbers.
Metric ruler, razor blades, potato pieces, paper towels, iodine
Purpose:
to identify why cells are so small.
Hypothesis:
Make a statement as to which potato cubes will diffuse the closer to the center of a cell (small, medium, large.
__________________________________________________________________________________________________________________________________________________________________________
Dimensions For Experiment
3 Cubes with sizes
A) 0.5 cm
B) 1.0 cm
C) 2.0 cm
Experimental Evidence:
1. Using a razor blade and paper towels, carefully cut 3 potato cubes using the dimensions from above.
2. Obtain TEACHER’S SIGN-OFF BEFORE you proceed!
3. Submerge the potato cubes (cells) into the iodine solution for 20 minutes.
4. While you are waiting for 10 minutes, calculate the surface area, volume, and surface area to volume ratio for each of the 3 potato cubes (cells).
AFTER 10 Minutes
5. Carefully remove the potato cubes (cells) from the iodine solution and place them on absorbent paper towels.
6. Cut each cell in half and observe the inside.
7. Draw each cell in detail showing the pattern of iodine throughout the potato.
Conclusion Questions: Use complete sentences.
1. What does the iodine used in the lab represent in the cell?
2. As the size of the cell increases, which increases faster: cell surface area or cell volume?
3. As cell size increases, what happens to the surface area to volume ratio? Give examples from the lab.
4. According to your drawings, in which cell (potato) did the iodine diffuse all the way to the center of the cube? Discuss the differences between the cells
5. Based on your understanding of cell size and the rate (speed) of diffusion,explain why there are NO GIANT CELLS! Discuss diffusion in your answer.
Conclusion:
Restate your Hypothesis and state whether or not if it is correct and why. Refer to your data and give numbers.