Solved by a verified expert:Experiment 2: Testing for Proteins
Data Tables and Post-Lab Assessment
Table 1: Protein
Presence Predictions
Sample with Test Tube Number
Initial Color of
Solution
Will There be Protein Present?
Final Color After
Biuret Solution is Added
1 – Albumin Solution
Light Blue
Yes
Violet
2 – Gelatin Solution
Light Blue
Yes
Violet
3 – Glucose
Light Blue
No
Light Blue
4 – Water
Light Blue
No
Light Blue
5 – Unknown
Light Blue
Yes
Light Violet
Table 2: Protein
Presence with Biuret Solution Results
Sample with Test Tube Number
Initial Color of
Solution
Final Color After
Biuret Solution is Added
Protein Present?
1 – Albumin Solution
Purple
Dark
violet/purple
settled on
bottom of
test tube
Yes
2 – Gelatin Solution
Violet
Violet
Yes
3 – Glucose
Light Blue
Light Blue
No
4 – Water
Light Blue
Light Blue
No
5 – Unknown
Light Blue
Milky Blue
No
Post-Lab Questions
1.
How
did your predictions from Table 1 compare to your actual results in Table 2? If
there were any inconsistencies, explain why this occurred.
My prediction was correct except for
the unknown solution.
2.
Identify
the positive and negative controls used in this experiment. Explain how each of
control is used, and why they are necessary to validate the experimental
results.
Positive control- gelatin solution since gelatin is high
in protein; it will definitely show a color change.
Negative control- glucose solution Glucose does not
contain protein so no color change will occur.
These controls are used so that we can assure that the
reactant, Biuret solution, is working correctly. They are necessary so we can
ensure the reactant is working and assume that theother results are accurate.
3. Write a statement to explain the
molecular composition of the unknown solution based on the data recorded in
Table 2.
4. What can you conclude about the
molecular make-up of egg whites? Use your results to support your answer.
5. What is the name of a common
macromolecule in egg white that would react with the Biuret solution?
6. What can you conclude about the
molecular make up of gelatin? Use your results to support your answer.
7. What is the name of a common type of
macromolecule found in gelatin that would react with the Biuret solution?
8. How might extreme hot temperature
affect the molecular composition of eggs?
9. What can you conclude about the
molecular make-up of the glucose solution? Use your results to support your
answer.
10. Glucose is one of the main sugars
absorbed during digestion. What type of macromolecule is glucose derived from?
11. Hemoglobin is a protein that is vital
to humans. What results would you expect if a hemoglobin solution was tested
with Biuret solution?
12. What major function does hemoglobin
perform?
13. Sickle cell disease is caused by a
mutation in hemoglobin. Research and discuss the structural effect on mutated
hemoglobin proteins.
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