Macromolecules Of LifeHandsOn Labs Inc Version

Macromolecules of Life
Hands-On Labs, Inc. Version 42-0085-00-01

Lab Report Assistant

This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.

Exercise 1: Testing for Proteins

Data Table 1: Biuret results.
Substance Tested
Predicted Results
Biuret Color & Number of drops added
1: Egg white
Contain protien
8 drops, purple
2: Pepsin none 8 light purple
3: Sugar none 8 none
4: Distilled water none 8 none

Questions

A. Which of the test tubes are the positive and negative controls? Test tube 1 and 2 are positive controls while 3 and 4 are negative.
B. What conclusions can be made about this experiment?
Egg white and pepsin contain proteins.
C. How might Biuret reagent be used in a practical real-life situation? To see if a cell or food has proteins in it.
D. How did the predicted results compare to the actual results?
I was correct on 3 of the 4. I predicted pepsin incorrectly.

Exercise 2: Testing for Sugars
Observations

Data Table 2: Benedict’s Reagent Results.
Test Sample
Predicted Results
Benedict’s results
#1 Glucose none positive
#2 Starch none negative
# 3 Onion juice
Sugars present positive #4 Distilled Water none negative

Questions

A. Which of the test tubes are used as the positive and negative controls? The positives are 1:glucose and 3: onion juice. The negatives are 2:Starch and :4 water.
B. How did the predicted results compare to the actual results?
I was wrong in thinking starch would have a positive result when it was actually negative.
C. What can be concluded from this experiment? I can conclude that glucose and onion juice contain sugars.

D. How might Benedict’s reagent test be used in a practical real-life situation?
You could test urine for sugars These would be a clue for diabetes.

Exercise 3: Testing for Starch
Observations

A. Write a hypothesis about whether a potato or onion has the most starch.
A potato has more starch than an onion.

Observations Table: Exercise 3
A. View of potato under pocket microscope. Magnification =

B. View of potato cells with IKI. Magnification =

Observations Table: Exercise 3
A. View of onion cells without IKI. Magnification =

B. View of onion cells with IKI. Magnification =

Questions

A. Which vegetable has the most starch? Potatoes contain more starch

B. What is the purpose of starch in vegetables? Hint: What is the function of stored sugar? It is how vegetables or plants to store energy or food. Like how a human stores it as fat.
C. How might the IKI reagent test be used in a practical real-life situation? It could be used to see if vegetables are getting enough sunlight because if they aren’t then they might not be creating starch.
D. Did the results differ from your hypothesis? Explain.
My hypothesis was correct. The results proved that potatoes do have more starch. My hypothesis was based on a guess but ended up being correct.

Exercise 4: Testing for Lipids
Observations

Data Table 3: Lipid test results.
Macromolecule Being
Tested
Hypothesis: contain lipid or not
Results from test
Potato

Onion

Oil

dH2O

Questions

A. What is the test substance?

B. Which test represents the control?

C. Which test contained the most test substance?

D. Did the results agree with the initial hypothesis in every case? Explain why or not.

Exercise 5: Making Mayonnaise
Conclusions

A. If you were given a piece of hot dog and a piece of carrot, using what you learned in these exercises, how would you analyze the composition of these materials?

B. What classes of compounds are present in living organisms that are not tested for in this exercise?