“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 1. What are 3 physical properties that can effect the rate at which things diffuse? 2. What is the driving force behind any diffusion? 3. Where do living cells get there food and water? 4. 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.