Lab 3 Cell Physiology Membrane Transport

Anatomy & Physiology 1 Lab Lab 3: Cell Physiology/Membrane Transport Objectives for this Lab: 1. 2. 3. 4. Review the components of the plasma membrane. Differentiate between active and passive transport processes. Explain the following passive transport processes: diffusion, osmosis and filtration. Determine how viscosity, temperature, molecular weight and molecular size impact the rate of diffusion. 5. Explain the process of osmosis and how solute concentration effects this process. 6. Predict what will happen to a cell when it is placed into an isotonic, hypertonic and hypotonic solution. 7. Describe the process of filtration and where in the body it occurs. Overview: The transport of materials across the plasma membrane is essential to the life and function of the cell. In order for the cell to carry out its many important functions, certain substances must be brought into the cell and waste products must be removed. Cells also produce substances that will be used by other cells once it is released. There are two basic forms of membrane transport: active transport and passive transport. Active transport requires the cell to produce energy in the form of ATP. No energy is required for passive transport and substances typically move down their concentration gradient. We will be discussing passive transport processes only in lab today. We will demonstrate the processes of diffusion, osmosis and filtration and what factors may effect these processes. Some of the experiments will be performed within your lab group and others will be conducted as a demonstration by your instructor. 35 Anatomy & Physiology 1 Lab Pre Pre-La -La -Lab bQ Que ue uestio stio stions ns ns:: true 1. True or False. The plasma membrane is made up of proteins and lipids. __________ 2. The cell must produce energy in the form of ATP to allow which transport process to occur? active _______________________________ 3. Which of the following statements are true regarding Diffusion? Check all that apply. true ______ a substance moves down its concentration gradient ______ the temperature of the solution will effect diffusion rate ______ a substance moves from a lower concentration to a higher concentration ______ it is a passive process ______ it requires energy in the form of ATP water 4. Osmosis involves the movement of what substance? ____________________ 5. As the viscosity of a substance increases, will this increase or decrease the rate of diffusion? decrease ____________________ 6. What would happen if a cell is placed into a hypertonic solution? Check all that apply. __ __ the cell would swell/burst __ ✔ __ water would move out of the cell __ ✔ __ the cell would shrink/crenate __ __ the water content of the cell would remain the same __ __ water would move into the cell 7. List 2 factors that would affect the filtration rate of a substance: surface area and size of the molecule viscosity and temperature ____________________________________________________ 8. True or False. The plasma membrane prevents the passage of all substances into and out of the false cell. ____________ 9. If temperature increases, how do you think this would affect the rate of diffusion? increases the rate of diffusion ________________________________________________________________________ 10. How do you think the molecular weight of a substance will affect its rate of diffusion? decreases the rate of diffusion ________________________________________________________________________ 36 Anatomy & Physiology 1 Lab Lab Exercises: Exe Exerci rci rcisse 3.1 3.1:: The EEfffec fectt of V Vis is isco co cosity sity o on nD Diffu iffu iffusio sio sion nR Rat at ate e In this experiment, you will be determining how viscosity effects the rate of diffusion. A. You will need 2 petri dishes: an empty one and one with agar B. Fill the empty petri dish half full with water. C. Place ONE potassium permanganate crystal in each dish. D. Observe the rate at which the potassium permanganate diffuses in each of the dishes and answer the question below. E. When finished, the agar dish will be disposed of in the trash can and the water dish will be poured into the waste container (do not pour down the drain). Results: 1. In which of the dishes did the potassium permanganate diffuse more rapidly? Explain why this would happen. The one with the water because it is less viscous. ________________________________________________________________________ Setup: 37 Anatomy & Physiology 1 Lab Exe Exerci rci rcisse 3.2 3.2:: The Effec fectt o off TTem em empe pe perat rat ratur ur ure e on Diff iffusio usio usion n Rat ate e In this experiment, you will be looking at the effect temperature has on the rate of diffusion. A. Collect 3 empty petri dishes B. You will be placing varying temperatures of water into each one: in one you will pour ice water, in one you will pour room temperature water and in the last you will pour hot water C. Place each dish on the petri dish outline provided in the lab and obtain a ruler to measure the diffusion rate. D. Place ONE potassium permanganate crystal into each water dish. Attempt to place the crystals simultaneously, as this reaction happens very quickly. E. Measure the rate of diffusion for each petri dish. F. When finished with this experiment, pour the contents of all the petri dishes into a waste container determined by your instructor. Do not pour anything down the drain. hot water Results: 1. In which dish did the potassium permanganate diffuse the most rapidly? _________________ 2. Describe the relationship between temperature and diffusion rate. as temperature increases, molecules move faster, therefore it will diffuse faster. ________________________________________________________________________ Exe Exerci rci rcisse 3.3 3.3:: The Effec fectt o off M Molecu olecu olecular lar We Weig ig ight ht on Dif iffus fus fusio io ion nR Raate In this experiment, you will be observing how the molecular weight of a substance effects its rate of diffusion. Potassium permanganate (molecular weight 158) and methylene blue (molecular weight 319) will be used in this experiment. A. Obtain a petri dish containing agarose gel. B. Using a drinking straw, make two small “wells” in the agar by gently pressing into the agar and removing a small amount of it. Do not go entirely through the gel...leave some underneath it. C. In one of the wells, place ONE drop of liquid potassium permanganate. D. In the second well, place ONE drop of methylene blue. E. Observe the diffusion rate of each. This may take up to 30 minutes to observe a noticeable difference. F. When finished, the petri dishes can be disposed of in the trash. the lighter Results: 1. Which substance showed the most rapid rate of diffusion? __________________________ 2. Based on this experiment, what is the relationship between molecular weight of a substance and its rate of diffusion? the higher the weight, the slower it will diffuse-- inversely proportional ________________________________________________________________________ 38 Anatomy & Physiology 1 Lab Exe Exerci rci rcisse 3.4 3.4:: The EEfffec fectt of PPaarti rticle cle Si Sizze o on n Diff Diffusio usio usion n Rate This experiment will demonstrate how the size of a substance or particle can affect how quickly it will diffuse. You will be determining if the following 4 substances are able to diffuse through a semipermeable membrane: starch, glucose, sodium chloride and egg albumin (protein). A. Fill a test tube with distilled water. B. Tie off the end of a dialysis tubing with string to form a bag. C. Fill the tubing with the solution containing starch, glucose, NaCl and egg albumin. D. Rinse the outside of the bag with distilled water. E. Immerse the filled bag into the test tube of distilled water and attach around the top of the test tube with a rubber band. Contents of the tubing should be fully immersed in the water. F. Let stand for 20-30 minutes. G. Remove the tubing (set aside) and run the following tests on the water in the test tube. Obtain 4 clean test tubes and add 2mL of the test water to each. Add the following substances to test for its contents: 1. Test for sodium chloride (NaCl): To one test tube, carefully add a few drops of silver nitrate. If NaCl is present, a white precipitate will form. Circle One: Positive or Negative Test ✔ 2. Test for Starch: To another test tube, add a few drops of Lugol’s solution. If starch is present, a dark blue or black color will appear. Circle One: Positive or Negative Test ✔ 3. Test for Albumin: To the next test tube, carefully add a few drops of nitric acid. If protein is present, a white precipitate will form. Must wear safety goggles when adding nitric acid. Circle One: Positive or Negative Test ✔ 4. Test for Glucose: To the last test tube, add an equal amount (2mL) of Benedict’s solution and place in the boiling bath for about 10 minutes. A green, yellow, orange or red precipitate will form if glucose is present. Circle One: Positive or Negative Test ✔ H. When finished, the contents of the tubing can be poured down the drain and tubing thrown in the trash. All other test tubes will need to be poured into the waste container on the side table. Setup: 39 Anatomy & Physiology 1 Lab Results: For Each of the following, explain your results: 1. Did starch diffuse through the tubing? Why or why not? no, starch is too large. Filtration driving force is pressure and gravity ________________________________________________________________________ 2. Did NaCl diffuse through the tubing? Why or why not? yes, the particles diffused and it is a small particle ________________________________________________________________________ 3. Did the egg Albumin diffuse through the tubing? Why or why not? no, it was too large, very large complex material ________________________________________________________________________ 4. Did Glucose diffuse through the tubing? Why or why not? glucose did diffuse because it is a small particle (if had boiling water) ________________________________________________________________________ 5. Based on these findings, what can be said for the relationship between particle size and the larger a particle is, the less ability to diffuse INVERSE diffusion rate? _________________________________________________________________ Exe Exerci rci rcise se 33.5: .5: Os Osmo mo mosis sis ((in in instr str struct uct uctor or de dem mo) Your instructor will be demonstrating the process of osmosis using decalcified eggs. Two eggs have been placed into acetic acid (vinegar) until the shells have become decalcified and then both were weighed. One egg was placed into a beaker of distilled water and the other was placed into a beaker of Karo syrup for at least 30 minutes. Both eggs were then removed from their solutions and weighed again. Your instructor will give you the initial and final weights of each: Egg in Distilled Water: Egg in Karo Syrup: failed experiment failed experiment Initial weight: __________________ Initial weight: ____________________ failed experiment failed experiment Weight after soaking: _________________ Weight after soaking: __________________ weigh more//hypotonic weigh less//hypertonic Weight difference: __________________ Weight difference: ___________________ Results: 1. Explain the difference in weight gain or loss for the 2 eggs? the one that weighed less- water left, the one that weighed more- water entered hypertonic-weighed less. 2. Would the corn syrup be a hypertonic or hypotonic solution? ____________________________ 40 Anatomy & Physiology 1 Lab Exe Exerci rci rcisse 3.6 3.6:: Cell To Tonic nic nicity ity (in instru stru structo cto ctorr d dem em emo) o) In this experiment, your instructor will be using varying concentrations of NaCl to determine if they are isotonic, hypertonic or hypotonic to blood cells. The concentrations will be 5%, 2%, .9%, .5% and .1% NaCl. A drop of blood has been placed into each of the varying NaCl concentrations and results will be observed. If the blood cells burst, the solution will become clear. If the cells shrink or do not change in volume, the solution will appear cloudy. Further explanation will be provided by your instructor. Results: For each of the following concentrations, determine if the blood cells underwent hemolysis, crenation or nothing and if the solutions were therefore, isotonic, hypertonic or hypotonic. NaCl Concentration 0.1% NaCl 0.5% NaCl 0.9% NaCl 2% NaCl 5% NaCl Lysis or Crenation Isotonic, Hyper or Hypotonic hemolysis hypotonic lysis neither crenates crenates hypotonic isotonic hypertonic hypertonic 0.9% NaCl 1. Which of these concentrations is isotonic to the blood cell? _____________________________ 2. What happens to a cell when it is placed into a hypotonic solution? it will burst and the solution will appear transparent ________________________________________________________________________ Exe Exerci rci rcisse 3.7 3.7:: Filt Filtrat rat ratio io ion n ((in in instr str struct uct uctor or de dem mo) In this experiment, your instructor will demonstrate how particle size and pressure can affect filtration rate of substances. Filter paper (representing the semi-permeable membrane) has been placed into a funnel tube. A solution containing water, starch, corn syrup and black pepper is then poured into the funnel. You will observe the appearance of the funnel paper and the filtrate will be tested for glucose and starch. Further explanation will be provided by your instructor. Results: 1. What was the appearance of the funnel paper? What is the explanation for this? funnel paper has a bunch of particles in, black pepper, The explanation is that it was not able to go through the filter paper ________________________________________________________________________ 2. Should the filtrate test positive for starch? Why or why not? negative for starch, starch is too big to pass through the filter paper. ________________________________________________________________________ 41 Anatomy & Physiology 1 Lab Pos Post-L t-L t-Laab Quest estion ion ions: s: 1. Why is it necessary for the plasma membrane of our cells to be “selectively permeable”? To allow some things in and some things to expel out of the cell to interact with the environment ________________________________________________________________________ 2. Why is it important that the solute concentration of the cytoplasm within our cells is the same as the solute concentration of the extracellular fluid? If it is not, there will be passive transport and things will move down their gradient, going from high conc. to low conc. ________________________________________________________________________ 3. Case Study: After running a marathon, an individual is brought into the ER with severe hyponatremia. Hyponatremia occurs when a severely dehydrated person rapidly consumes large amounts of water. This causes the amount of sodium in the blood to drop drastically and the amount of water to greatly increase (blood becomes hypotonic). If the blood circulating though the brain is extremely hypotonic, what effect might this have on the brain cells? the cells will burst because there is too much water in them ________________________________________________________________________ What symptoms might this person exhibit? severe headache ________________________________________________________________________ List a couple of health care professionals that may be involved in the care and treatment of this person. (think short term and long term, educating patient, etc) EMT, doctor, physical therapist, nutritionist ________________________________________________________________________ 42