For my biology lab experiment I mixed glucose and starch solution (clear) in a b
ID: 717003 • Letter: F
Question
For my biology lab experiment I mixed glucose and starch solution (clear) in a bag and then soaked it in a beaker with distilled water (clear) for 60 mins. After 60 mins the solution in the bag and beaker were still both clear. I did a glucose test strip for the solution in the bag and the color was dark green. I did an IKI indicator for the water in the bag and it came back dark blue. I then tested the solution in the beaker, glucose strip came back light green and the IKI indicator color came back very light amber. So on my lab question it is asking me to explain why the materials moved the way that they did in beaker / bag 1 in my dialysis bag experiment. ( Give info on water, glucose and starch.)
Explanation / Answer
Hello!!!
The dialysis bag in your lab experiment act as the selectively-permeable membrane. A selectively permeable membrane is a membrane which allows only few materials to pass through it depending on its pore size. Thus, glucose being a monomer can easily pass through the dialysis bag membrane but starch being a polymer faces a difficulty.
The glucose strip test involves the use of an enzyme called as Glucose oxidase. This enzyme upon action on glucose, will convert glucose into gluconic acid, thus, making the strip to change colour. On the other hand, Iodine forms a complex with starch molecules making the solution turn dark blue if iodine is present and amber coloured if not.
Thus, after half an hour of your experiment, glucose must have passed the dialysis bag membrane and the water in beaker got some amount of glucose which gave the strip test light green colour. Also, starch wasn't able to pass the dialysis bag and hence, KI test showed amber colour.
Feel free to ask your queries in the comment section.
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