Diffusion Lab Draw a picture of setup Tests Label where Iodine, Sugar and Starch are Tests Starch Test Color Before Test Color After Test Sugar Test Define Diffusion in your own words.

Diffusion Lab (continued) Draw arrows to where things moved Conclusion Explain what direction each of the molecules wanted to move. Explain how you know what moved and what didn’t. Why did some molecules move and other didn’t? (Hint: Look at the molecules) How does this experiment and its results relate to diffusion in cells? (Hint: Remember where cells get their food, water & oxygen)

Osmosis Lab Create a lab sheet by folding your paper into thirds from top to bottom. Label the sections: Pond Water (95%), Salt Water (78%) & Distilled Water (100%) Take a leaf tip from a sprig of Elodea. Wet mount the leaf tip with pond water (95% water). Draw one of the cells you see. Label the cell wall, cell membrane and chloroplasts. Return to the lab table and add one drop of salt water to the leaf and reapply coverslip. Draw one of the cells you see. Label the same parts. Return to the lab table, rinse the leaf with the distilled water, then re-mount with a drop of distilled. Draw one of the cells you see. Label the same parts. In each of your drawings, label the concentration of water inside and outside of the cell. Then draw arrows to where the water moved. Under the drawing, label each as: ISOTONIC, HYPERTONIC, HYPOTONIC. On the top back, answer: How could you tell if water moved in or out of the cell? Be specific, detailed and use the correct terms.

“Why are cells so small?” Pre-lab Cube Size Surface Area (cm2) Volume (cm3) Simple Ratio Depth of diffusion (cm) 3 cm 2 cm 1 cm .01 cm What are 3 physical properties that can effect the rate at which things diffuse? What is the driving force behind any diffusion? Where do living cells get there food and water? Approximately, how big is one cell?

Cells So Small Lab Questions How do you know that NaOH diffused into the agar cubes? Is the depth diffused the same or different for each cube? So, does one diffuse faster than another? Make two columns, label one “Size of Cubes” & the other “Ratio” In the first column, list the agar cubes in order of size from largest to smallest (3cm – 1cm). Then in the second column, list the cubes in order of the cube SA:Vol ratio, from largest to smallest. What can you say about size of the cube compared to its ratio? What happens to the surface area to volume ratio as cubes get bigger? Are cells bigger, the same as or smaller than, the .1 cm cube? How do cells get their food and water? Explain why cells remain small regardless of the size of the organism.