Cell+size+lab

=Cell size lab= 1. Take a 3 cm X 3 cm X 6 cm agar cube.

2. Cut it into 3 cubes measuring 3cmX3cmX3cm, 2cmX2cmX2cm, and 1cmX1cmX1cm.

3. Place the cubes in your beaker and just cover with sodium hydroxide. Make sure they stay submerged.

4. Let the cubes sit for 10 minutes.

5. While the cubes are soaking fill in the table below under surface area. Calculate surface area by finding the area of one side and then multiplying by the total number of sides. Use the formula: SA = l x w x # sides. Remember a cube has 6 sides.

Example: 5 cm cube SA = 5cm x 5cm x 6 SA = 150 sq cm

6. Calculate the volumes and complete that portion of the table. Show your work. To find a cube's volume, use L x W x H. Example: 5 cm cube V = l x w x h V = 5cm x 5cm x 5cm V = 125 cubic cm

7. Find the surface area to volume ratio and complete the correct column of the table. Divide surface area by volume and reduce to the lowest fraction. Show your work. Use only the number values when calculating. Example: 5cm cube SA/V = 150/125 SA/V = 1.2

8. Remove the cubes after 10 minutes and carefully cut them in half.

9. Measure the amount of diffusion in centimeters and record it in the table (Diffusion depth.)

10. Calculate the rate of diffusion and record in the table. This is calculated by dividing the amount of diffusion by the time (10 minutes). Show your work. Use this formula: R = d/t R=rate of diffusion d=distance t=time

=Data Table= 1. Create a table of 6 columns and 4 rows. Column headings are: Cube Size, Area of Cube, Volume of Cube, Surface Area to Volume Ratio, Distance of Diffusion, Rate of Diffusion 2. After measuring and doing your calculations, fill in the chart. If units are needed, place them in the box with the appropriate heading.

Analysis: 1. Compare and contrast the three cubes after they were sliced in half. 2. Which "cell" seemed to be most and least efficient at getting outside substances into the cell? Explain. 3. Which of your calculations seems to explain what you observed in your cell models? Why do you think so? 4. Speculate on a relationship between cell size and efficiency. Your statement should resemble a hypothesis.


 * Assessment**:




 * Homework #5**: Create a paragraph(s) answering the following:
 * Paragraph stating original hypothesis and any changes in hypothesis during or at the end. Include observations and what you learned.
 * Discussion of surface area to volume ratios, diffusion depth (mm), diffusion rate (mm/min), and what you learned in comparing the three different cells.
 * Answer the resulting question: Why are cells small? (Hint: focus on the ratio and what that means, think which cell was the best cell, include supporting information from your data using appropriate vocabulary) What does this mean in terms of surface area and volume to the functioning of the cell? Why do some cell organelles have folded membranes and some do not (give examples of each and the roles of the cell organelle - why do some need to have folded membranes inside the organelle)?