A Lab on diffusion and osmosis. Basically, we had a15ml strip of dialysis tubing that was soaked. We tied a knotto form a sack. We added 3ml of starch, gelatine (protein),glucose and NaCl into the sack and we tied the sack with another knot. We rinsed it with a little water and placed it into a250ml beaker with distilled water. We heated it to37oCelsius. We waited for 30 minutes for themolecules to move out of the sack and into the surrounding waterbath. While waiting, we tested indicators to determinewhether a certain molecule has moved through the semi permeablemembrane. We removed 80ml of water from the beaker anddistributed 20ml into each of 4 beakers.
Indicators--glucose-benedict's soln, NaCl-AgNO3,starch-iodine, protein-biuret soln
There was a presence of glucose and NaCl in the water bathwater when we tested using indicators.
questions...
a)tyrosine is an amino acid. If we added an enzymeinvolved in the digestion of proteins to the dialysis sack, wouldyou expect to get a positive test for tyrosine in the water bath?Explain.
b)in a cell, turgidity is due to internal pressure. Describe the state of turgidity of the dialysis sack over theduration of the investigation. If there were changes,describe why they occured.
c)over a long period of time, you may see the presence of somestarch in the water bath. Give 2 possible explanations.
d) suggest a reason why quick movement of each molecule intoor out of a cell might be important in functions within the humanbody.