Answers to Amali Proses Sains Pg 15-17

Aim : To study the movement of substances across a semi permeable membrane.

Hypothesis: Molecules which are smaller than the pores of the Visking tubing are able to move across the plasma membrane

MV : Size of solute molecules

RV : Colour of Iodine/Benedict  solution

FV : Temperature/time

Solution in	Content	Iodine test		Benedict test
		Initial	Final
Visking tubing	Glucose solution + starch suspension	Colourless	Dark blue	Red precipitate
Beaker	Distilled water + iodine solution	Yellow	Light yellow	Red precipitate

Discussion

1.       Iodine molecules are smaller than the starch molecules. Thus the iodine molecules are able to move into the visking tubing while the starch molecules cannot move out from the visking tubing.

2.       Glucose molecules are smaller than the starch molecules.

3.       Starch needs to be hydrolysed to glucose in the alimentary canal so that the glucose molecules are small enough to diffuse into the epithelium cells of the villi and into the blood capillaries.

Conclusion

Yes, the hypothesis is accepted. Molecules which are smaller than the pores of the Visking tubing are able to move across the plasma membrane.