1 Tabulate your results including whether haemolysis occurred, the time of haemolysis and whether the solution is hyper-, hypo- or iso-tonic and whether it is hyper- hypo- or iso-osmotic to normal red blood cells. Explain the results in terms of tonicity, osmolarity and ability to penetrate.

2 It should be clear to you that when considering haemolysis of red blood cells, NaCl, sucrose and urea can be divided into two distinct classes. Divide these substances into two classes and state clearly the basis of this classification. If you were given a compound X, outline how you would decide by a simple experiment to which class it belongs?

	NaCl M	sucrose M	urea M	stock				H2O mL	haemolysis (sec)	tonicity	Osmolarity(mM)
				0.308 M NaCl mL		1 M sucrose mL	10 M urea mL
1	0.154	nil	nil	5		0	0	5	N/A	Iso	308
2	nil	0.280	nil	0		2.8	0	7.2	N/A	Iso	280
3	nil	nil	0.280	0		0	0.280	9.72	1 sec	Hypo	0
4	0.154	nil	1.00	5		0	6	4	N/A	Iso	308
5	nil	0.280	1.00	0		2.8	1	6.24	N/A	Iso	280