Diffusion - Lab report for bio1101 summary, materials, results, etc PDF

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Lab report for bio1101 summary, materials, results, etc...

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New York City College of Technology Biology 1101 Week VIII - Diffusion Exercise 2: Observe  diffusion as affected by molecular weight Abstract: In this exercise, we will use Permanganate with a molecular weight of 158/mole and malachite green with a molecular weight of 364g/mole and ager. We will wait approximately 1 hour to see how much it traveled/diffused through ager. Materials: ● Test Tubes ● Ager ● Permanganate ● Malachite green Procedure: 1. Place ager in two tubes. 2. In tube 1 place Permanganate. In tube 2 place malachite green. 3. Wait 1hr and record results. Conclusion: From 9:10 AM to 10:10 AM permanganate diffused faster due to its lighter molecular weight.

Exercise 3: Observe Diffusion Across A Selective Membrane Abstract: The purpose of this experiment is to observe diffusion through a membrane. Movement through a membrane being a folded and tied dialysis tube from high to low concentration.The two indicators we will use are phenolphthalein and Iodine. With phenolphthalein it will turn red if the solution is basic. For iodine if starch is present we will see a color change of light brown to dark blue. Materials: ● Dialysis Tubing ● String ● Water ● Phenolphthalein ● Starch Suspension ● Beaker ● Dropper ● Sodium Hydroxide

● Iodine Procedure: 1. Place dialysis tubes in water and allow them to soak. 2. Remove two tubes from the water and tie each tube on one end with string. Fold the ends before tying to ensure no leaking occurs. 3. Open tube 1 and add 10 ml of water and 3 drops of phenolphthalein. Tie the tube. 4. Open tube 2 and add 10 ml of starch suspension.Tie the tube. 5. Rinse the outside of the tubes in tap water. 6. Fill a beaker with 200ml of tap water and add 10 drops of 1M sodium hydroxide. Place tube 1 in the beaker. 7. Fill another beaker with 200ml of tap water and add 20-40 drops of iodine.Place tube 2 in the beaker. 8. Observe the color change. Data: Tube 1: Fuschia/ Purple color Tube 2: Yellow Conclusion: When you mix sodium hydroxide with the phenolphthalein (the indicator), the solution will be purple as we saw in tube tube 1. When you mix iodine with starch you get a yellow color due to iodine being a starch indicator. Exercise 6: Observe Hemolysis Abstract: The purpose of this experiment is to observe osmosis in living cells are placed in hypertonic, hypotonic and isotonic environments. For blood cells placed in water the cells are destroyed by the influx of water which is where the word lysis comes from and hemo means blood. It's the destruction of blood cells by water. We will be using fresh sheep's blood and not only water but NaCl to destroy the cells. Materials: ● Test tubes ● Distilled water ● 0.9% NaCl ● Fresh sheep’s blood ● 40%NaCl Procedure: 1. Using 5 tubes follow the chart and add the correct concentration of distilled water or NaCl to the blood. 2. Hold tubes in front of paper with writing and note if one can read each.

Data: Tube

Readable or Unreadable

1

Readable

2

Readable

3

Readable

4

Unreadable

5

Unreadable

Conclusion: The tubes with distilled water1-3 were easy to read through since the water destroyed the cells due to the hypotonic environment. For tubes 4 and 5 due to the high concentration of NaCl being hypertonic the tubes were unreadable.

Questions: 1. Membranes protect the cell from its surroundings and controls what enters and exits the cell. 2. Active transport is movement of molecules across a cell membrane from  low to high requiring energy, with the gradient. Passive transport is movement o  f molecules across a cell membrane f rom high to low going against the gradient. 3. The fluid mosaic model is a model of a membrane with a plasma lipid bilayer and protein inside. 4. Permeability of membranes is selective. Molecules govern their movement through the lipid bilayer. Small nonpolar molecules pass through the membranes easily and polar molecules are retained. 5. The chemical components of membranes are a lipid bilayer, proteins, cholesterol, and carbohydrates....