BI 205_Week_4_lab_2017.docx - Benjamin Miller/Bi 205/Sec...

Benjamin Miller/Bi 205/Sec 402
2/4/17
Week 4 Lab – Osmosis and Diffusion
Record the volumes of water and stock solution that you used to make 200 mL of
15% sucrose below. You will need the V
1
value of the stock solution + water, so that it
will add up to a total volume of 200 ml.
mL of water needed = ____100________
mL of 30% stock sucrose solution needed = ____100__________
Describe your “unknown” sugar solutions here. For example, you could say, “I
dissolved 1 tablespoon (~15 mL) of honey in 100 mL tap water, and poured 5 mL of
this into one dialysis bag, and I poured 5 mL of room temperature orange juice into
the other dialysis bag.”
Two ml of maple syrup was placed in 20 ml of purified water; this was placed in the
dialysis bag.
Five ml of o.j. was piped into the dialysis bag.
In addition, take a photograph of your experimental set-up (the dialysis bags
in the beaker), and insert it here.

7. Measure the weights of your four filled dialysis bags using the digital scale. Record
your measurements below:
Blue rubber band bag = __6.7 g____________
Red rubber band bag = ____6.5 g___________
Yellow rubber band bag = __6.8 g_____________
Green rubber band bag = ____6.3 g___________
White rubber band bag = _____6.9 g__________
Using the examples provided in the link above, develop a hypothesis for your
experiment. Include your hypothesis, along with supporting scientific
reasoning in the space below.
I hypothesize that those solutions contained within the dialysis tubules which have
concentrations of polysaccharides hypotonic (relative to the external solution of
15% sucrose) will experience a net loss of H
2
O. Further, those tubules which contain
solutions which are hypertonic (relative to the external solution) will experience a
net gain of H
2
O. Therefore, the weight of those tubules experiencing net water loss

will be less than the original measurements indicated in the table above, whereas
the weight of those tubules experiencing net water gain will be greater than the
original measurement recorded in the table above.