• What molecules can pass through a semi-permeable membrane? In this lab study we tested carbohydrates such as starch and glucose, as well as solutions like Benedict’s and Lugol’s to see if they would cross the membrane of a cell but since we can't actually see that happen we used dialysis tubing (acts as the cell membrane).
• My prediction was that glucose and Benedict’s could pass the semi-permeable membrane but starch and Lugol’s wouldn't be able to.
• The purpose of this study is to be able to identify what molecules can pass through a semi-permeable membrane and also to differentiate between diffusion and osmosis.
• To perform their functions, cells must maintain their state in an unsteady …show more content…
Seal the end if it is not already closed. Next, pick up a pipette and fill it with glucose. (Use this pipette only for glucose) then release the glucose into the dialysis tubing. Place four more pipettes full of glucose into the dialysis tubing. Now it is time to get another pipette (not the one used for glucose) and fill it with starch and release it into the dialysis tubing. Repeat this 4 (four) more times until there is a total of 5 pipettes of glucose and 5 pipettes of starch in the dialysis tubing. Mix the solution. Next, seal the dialysis tubing completely and make sure there is little to no air left in the dialysis tubing. Rise the bag with water. Next, fill a 400ml beaker with 300ml of water. Add 5 pipettes of Lugol´s into the 300ml of water. Mix the solution gently. Place the dialysis tubing bag into the 400ml beaker and leave for 30 minutes. After 30 minutes remove the bag and record your findings. Get 3 test tubes and label them “control” “bag” and “beaker” Next fill an unused pipette with water and pour it into the control test tube. Open the dialysis tubing and fill a pipette of the solution inside using an unused pipette. Repeat again and pour into the bag test tube. Place two pipettes of the beaker solution into the beaker tube. Add one pipettes of Benedict´s into each tube Heat all tubes for three minutes. Record