View the step-by-step solution to: Table 4 Starch Diffusion– Initial Final Color Starch

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Table 4 Starch Diffusion–
Initial Final
Color Starch present? Color Starch present?
Beaker Yellowish No Black (?) Yes (?)
Dialysis tube* Purple Yes Green (?) No (?)

Table 5 Glucose Diffusion –
Initial Final
Color Glucose present? Color Glucose present?
Beaker Yellow No Black (?) No (?)
Dialysis tube* Green Yes Green (?) Yes (?)

Course Hero Question - Which substance(s) crossed the dialysis membrane and moved into the beaker solution?

Criteria – No word limit and no page requirement; don’t forget to mention what evidence from your results proves this.

Notes -
1. Dialysis bag solution consists of 5ml of glucose solution and 5ml of starch solution; minus 2ml mixture of both for the control point.
2. Beaker 4 solution first consisted of the 2ml mixture of the glucose and starch solution; then added a few drops of IKI solution.
3. Beaker 2 solution first consisted of 80mil of water; then added the dialysis bag of mixed starch and glucose solutions to sit in; then added 2ml of the IKI solution to the 80ml of water.
4. In tables 4 & 5, I know the initial colors are correct, not sure of the final colors.

lab 6: Diffusion

2: Concentration


and membrane


We will dialyze a solution of glucose and starch to observe:

The directional movement of glucose and starch.

• The effect of a selectively permeable membrane.
In this lab, we will be using an indicator to test for the presence of starch and glucose. An indicator is a
substance that changes color when in the presence of the substance it indicates

1Scm Dialysis tubing**
4 100mL Beakers
Glucose solution

4 Small rubber bands
7 Graduated pipettes

1% Starch solution

Watch *
"You must provide

4 Glucose test strips


Iodine-Potassium Iodide (IKI)

** Cut to exact length

You will need dialysis tubing in subsequent experiments,
specified in the directions.

so be sure to cut the amount

Dialysis tubing can be rinsed and used again if you make a mistake.
Dialysis tubing must be soaked in water before you will be able to open it up to create
the dialysis "bag". Follow the directions for the experiment, beginning with soaking the
tubing in a beaker of water. Then, place the dialysis tubing between your thumb and
forefinger and rub the two digits together in a shearing manner. This should open up
the "tube" so you can fill it with the different solutions.


Fillone 100mL beaker with SOmLwater and submerge the dialysis tube for 10 minutes. Filla
second beaker with 80mL water (this is the one you will put the filled dialysis bag into in Step


After the ten minutes have passed, remove the dialysj,stube and dose one end by folding over
3cm of one end (bottom). Fold it again and secure with a rubber band (use two if necessary).


Make sure the closed end will not allow a solution to leak out. You can test this by adding a few
drops of water and looking for leakage. Pour the water out before continuing.


lab 6: Diffusion

Do not allow the open end of the bag to fall
into the beaker. If it does, remove the
tube and rinse thoroughly with water
before refilling with a starch/glucose
solution and replacing it in the beaker.


Use a graduated pipette to add 5ml of glucose solution to a

Indicator Reagents

third beaker and label it "Dialysis bag solution". Using another graduated pipette, add 5mL of starch solution to the
same beaker. Mix by pipetting the solutions up and down

IKI Solution:


the pipette six times.


5. Transfer 8mL ofthe dialysis bag solution (glucose and starch) J
into the prepared dialysis bag. The remaining 2mLwi" serve
as a sample to test for the presence of glucose and starch (to
act as a control and show that both glucose and starch were
present in the solution poured into the dialysis bag).

= no starch

Purple/Slack = starch
Glucose Test Strip:

= no glucose


= glucose

Label the last (fourth) beaker "Beaker solution", and using a \
clean pipette, transfer a sample of 2mL of the water in the
second beaker to this beaker (to act as another control to show that the water the dialysis bag
is placed in does not contain starch or glucose).

7. Test for the presence of glucose by dipping one glucose test strip into the dialysis bag solution
sample (third beaker) and another strip into the beaker solution sample (fourth beaker). Wait 1
minute, then observe the color of the test strip. Record your results in the following tables
(Tables 4 and 5).

Next, add a few drops of IKIsolution into both sample beakers (the third and fourth beakers).
Record your observations in Tables 4 and 5.


Place the filled dialysis tube into the second beaker filled with 80mL of water with the open
end draped over the edge of the beaker as shown below.

10. Use a pipette to add 2m' of IKIsolution to the beaker water. Record the initial color of both
the beaker water and the solution in the dialysis tube in tbe table below (Table 4).
11. After the solution has diffused for 60 minutes, remove the dialysis tube from the beaker.

Lab 6: Diffusion

12. Again, test for the presence of glucose by dipping one glucose test strip into the dialysis bag
directly and another strip into the beaker solution. Again, wait one minute before reading the
results of the test strip. Record your results for the presence of glucose and starch in the following Tables 4 and 5.

Table 4: Starch Diffusion

Table 5: Glucose Diffusion


VVhichSJbstanre crossed t he dialysis membrane? VVhat evidence from your results proves


VVhat molea.Jlesremained inside of the dialysis bag?



diffused through the bag, did all of the molecules diffuse out?

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Biology - 8351397.doc

Table 4 Starch Diffusion–



Starch present?


Starch present?











Table 5 Glucose...

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