Block Dimension These ar Table 2: Results from Surface Area to


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Block Dimension These ar Table 2: Results from Surface Area to Volume Experiment Block Dimensions Surface Area (cm2) Volume (cm 3) Time Required for Complete Color Change Distance of Diffusion 1 cm x 1 cm x 1 cm 1 cm x 2 cm x 2 cm 1 cm x 1 cm x 6 cm Calculate the surface area to volume ratio for each block: (Note: To determine surface area to volume ratio, divide the surface area by the volume.) 1 cm x 1 cm x 1 cm: 1 cm x 2 cm x 2 cm: 1 cm x 1 cm x 6cm: Post-Lab Questions (Answer in complete paragraphs) How did the surface area affect the diffusion of the block? How did volume affect the diffusion? How did the surface area to volume ratio affect the diffusion? Which of these had the greatest effect on the diffusion of the block? How does this experiment demonstrate the need for larger cells to divide? Determine the surface area, volume, and surface area to volume ratio for the following three blocks. Then, indicate the one you believe would be the most efficient as a cellular morphology, and write a summary stating why. A. B. C. ANSWERS Surface area:Surface area:Surface area:Which of these three blocks would be the most efficient as a cellular morphology, and write a summary stating why. Table 7: Water Displacement per Potato Sample Potato Type Potato Observations Sample Initial Displacement (mL) Final Displacement (mL) – Step 11 Net Displacement (mL) A B A B Post-Lab Questions How did the physical characteristics of the potato differ before and after the experiment? Did it vary by potato type? Different types of potatoes have varying natural sugar concentrations. Explain how this may influence the results for each type of potato. Based on the data from this experiment, hypothesize which potato has the highest natural sugar concentration. Explain your reasoning. Did water flow in or out of the potato cells in each of the samples examined? How do you know this? What do your results show about the concentration of the cytoplasm in the potato cells at the start of the experiment? Experiment 3: Osmosis – Direction and Concentration Gradients In this experiment, we will investigate the effect of solute concentration on osmosis. A semi-permeable membrane (dialysis tubing) and sucrose will create an osmotic environment similar to that of a cell. This selective permeability allows us to examine the net movement of water across the membrane. You will begin the experiment with a 30% sucrose solution, and perform a set of serial dilutions to create lower concentration solutions. Some of the sucrose concentrations will be membrane permeable; while others will not be permeable (can you determine why this is?). Materials 60 g Sucrose Powder, C12H22O11 (3) 250 mL Beakers 4 Waste Beakers (any volume) 8 Rubber Bands (two red, two blue, two green, and two yellow) 10 mL Graduated Cylinder 100 mL Graduated Cylinder Stopwatch Permanent Marker *Water *Scissors *Paper Towel *(4) 15 cm. Pieces of Dialysis Tubing *You must provide *Be sure to measure and cut only the length you need for this experiment. Reserve the remainder for later experiments. Procedure Use the permanent marker to label the three 250 mL beakers as 1, 2, and 3. Cut four strips of dialysis tubing, each 15.0 cm long. Fill Beaker 3 with 100 mL of water and submerge the four pieces of dialysis tubing in the water for at least 10 minutes. After 10 minutes, remove one piece of tubing from the beaker. Use your thumb and pointer finger to rub the dialysis tubing between your fingers. This will work open the dialysis tubing. Wrap one of the yellow rubber bands around one end of the dialysis tubing. Leave approximately 1 – 2 in of tubing below the rubber band. Tie a knot in the remaining dialysis tubing just above or just below the rubber band. This will create a seal and ensures that solution will not leak out of the tube later in the experiment. To test that no solution can leak out, add a few drops of water to the tubing and look for water leakage. If any water leaks, tighten the rubber b

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