1. 1. Cut 3 cubes from your agar block 1. 1x1x1 (cm) 2. 2x2x2 (cm) 3. 3x3x3 (cm) 2. Fill 3 separate beakers with 20mL acetic acid solution 3. Drop a cube in each beaker 4. Wait 10 minutes and then remove cubes onto white sheet of paper 5. Cut your cubes in half and measure the distance the acetic acid penetrated. While waiting the 10 minutes: workbook pages 31-34

2. Cube dimension Surface area (cm2) Volume (cm3) SA/V ratio% penetrated Sketch of cube 1cm 2cm 3cm % penetrated instructions: 1.Calculate total volume of each cube (volume = L x W x H) 2.Calculate volume that did not turn pink. (That is, calculate total volume of the small portion of the cube that did not turn pink – use the same formula L x W x H) 3.Calculate volume diffused = total volume – volume not pink. 4.Calculate % diffusion = Volume diffused /total volume x 100 % penetrated instructions: 1.Calculate total volume of each cube (volume = L x W x H) 2.Calculate volume that did not turn pink. (That is, calculate total volume of the small portion of the cube that did not turn pink – use the same formula L x W x H) 3.Calculate volume diffused = total volume – volume not pink. 4.Calculate % diffusion = Volume diffused /total volume x 100

3. 1. In terms of maximizing diffusion, what was the most effective size cube that you tested? Why was that size most effective at maximizing diffusion? (What affects the rate?) 2. If a large surface area is helpful to cells, why do cells not grow to be very large? 3. How does your body adapt surface area-to- volume ratios to help exchange gases/nutrients? Reminders: Wednesday: Exam (Homework: Read chapter 6 and finish agar lab, and WB) Thursday: Test corrections (lab due, chapter 6 due) homework: ch.6 quiz Friday: Cell structure discussion/analogies (Homework: Finish analogies, And bring in materials for cell membrane.