EXPERIMENT 1: DIALYSIS
PROCEDURE 1: Making of dialysate:
Materials:
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Cellophane (12X12 in)
Milk
Distilled water
Beaker
Stirring rod
Process:
1. Cut and fold the
cellophane
3. Collect all the
edges of the
cellophane and tie
with string
4. Suspend the bag
from an air stand
into a 500 ml
beaker. Dialyze
milk for 1 hour by
constant stirring.
2. Put the milk on the
folded cellophane
Result
Before Stirring
After Stirring
Observation:
After an hour of constant stirring, the color of distilled water in the beaker became hazy/blurry. The
longer it was stirred, the more it became hazy/blurry. In this experiment , the cellophane serves as the
membrane that allows the ions to pass through without diffusing the particles of the milk, hence the
color and quality of the water.
PROCEDURE 2: TEST OF PROTEINS
A.
Dialysate
Appearance: hazy/ blurry
Dialysate with 25%
trichloroacetic acid
solution
Appearance: clear water
Observation:
Based on our observation, the result of the lab test for protein shows that the dialysate solution in the
test tube becomes clear and free from visible particles after adding 1ml of 25% trichloroacetic acid.
B. Checking the sensitivity of the test
Diluted milk with trichloroacetic acid:
A drop of milk
diluted in 10 ml
distilled water
Appearance: water looks solid white
Diluted milk with
25% trichloroacetic
acid solution
Appearance: hazy with solid particles of milk
Observation:
Based on our observation, the result shows that some of the milk particles from the diluted milk were
floating on the surface and around the solution after adding 1ml of 25% trichloroacetic acid.
Comparison of solution A
(left) and Solution B
(right)
EXPERIMENT 2: TEST FOR SPECIFICITY OF ENZYME ACTION
Materials used:
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1 ml cooked starch (for test tube 1)
1 ml 0.1% glycogen solution (for test tube 2)
1 ml concentrated potato juice (for test tube 1&2)
Iodine solution (for test tube 1&2)
Process:
1. Preparing test tubes 1 and 2 with 2ml of 0.02M phosphate buffer, pH6.7, and 1ml
of 0.9% NaCl solution
2. 1ml of cooked starch and
concentrated potato juice was added
to test tube 1.
And 1 ml of 0.1% glycogen solution
and concentrated potato juice was
added to test tube 2.
RESULT:
1. After putting a droplet of iodine to the spot plate with the mixture in test tubes 1 and 2, the mixture changed
its color to black and then changed to dark violet.
2. The droplets in the spot plate doesn't really show the difference of color in each droplet, all of which showing
dark violet color.
However, when we put the mixture on the tissue, we saw subtle difference of the color contrast in each
droplet, where some have darker shade of violet (from 11th drop) and some have lighter shade of violet (from
1st drop)
3. We then observed that the longer the time of the mixture of iodine and substance on the spot plate, the
lighter color it gets.
Performed by:
Group 5
Meah Trinidad
Jhenny Zacate
Julienne Redona
Franziska Zimny
Ann Tabuquilde