Question

I repeated the same cell experiment five times and found that my cell gained weight (twice), didn’t change weight (once), and lost weight (twice). Why did the weight gain/loss vary so much in my experiment? Provide at least 3 hypotheses and a brief rationale for each.

The experiment was diffusion across dialysis tubing.

Answer 1

Ans:- Weight loss and weight gain in your experiment is due to permeability of the membrane. Some molecules pass through the membrane while some doesn't.

1. The permeability of the tubing to glucose , iodine and starch was tested. The dialysis tubing was clipped to form a bag so that glucose and starch was fed into the bag through other end and also clipped to avoid the seeping of solution.water with several drops of iodine added to it until it was visibly yellow amber was added to 400ml beaker. The bag is yhen placed in a bekaer and left there for 30 minutes. the colour of the solution in the bag changes to blue-black. this shows that iodine was able to pass through the membrane into the bag. the solution in the beaker become pale yellow. this shows that starch didn't pass through the membrane to the beaker. this experiment consists of two tests- the test for glucose and the test for reducing sugar.