1. HONORS BIOLOGY Testing Macromolecules

2. Detecting if a substance is present You won’t be determining how much
Qualitative
Detecting if a substance is present
You won’t be determining how much

3. SAFETY Must wear goggles and aprons the whole time!!!!!!
If the chemicals react with proteins, they will react with you.
Iodine stains.

4. SAFETY Cut onion and potato into diced pieces
Rinse razor blades under water, do not wipe across the blade
Put used blades at the end of the period in the “used razor blades” container on the cart

5. 5-6 boiling chips
Used so the liquid boils smoothly without becoming superheated or bumping

6. Controls Positive Control Negative Control
Absolutely expect to see the result
Use the substance
(starch, glucose, etc.)
Negative Control
Absolutely expect to NOT see the result
(may use water)

7. Reference Sheets on the Back Cart
Iodine Test
Fat (lipid) test
Protein test

8. GLUCOSE TEST: Recording Benedict’s Results
blue no sugar
blue/green trace
++ green little sugar
+++ yellow some sugar
++++ orange/red much sugar

9. Benedict’s Glucose Test

10. Iodine Starch Test
negative
positive

11. Polysaccharide Monomer = glucose Disaccharide (sucrose)
Monosaccharide (glucose)

12. Hydrolysis “break with water” to make monomers

13. Sucrose, A Disaccharide
Glucose Fructose

14. Monosaccharides (Glucose)
What color is Benedict’s before testing?
What is it used to test the presence of?
glucose

15. Which tests are positive for glucose
Which tests are positive for glucose? Which sample shows the highest amount of glucose?

16. Which is a positive test for glucose?
What do the various colors mean?

17. Iodine is what color at start? Which test tube below is a positive test? Which is the control?
Left is potato starch Right is distilled water

18. Which test is positive for starch?
Add iodine
Look for blue-black color

19. Would you say the iodine and potato (left) is a positive or negative test?
Would you say the iodine and onion (right) is a positive or negative test?

20. How do glucose molecules and starch molecules compare?
Starch is made of chains of glucose
starch

21. We will be substituting ULTRA SOY for chicken broth
LIPIDS (fats/oils)
We will be substituting
ULTRA SOY for chicken broth

22. Sudan IV and Milk Done as a demo because may cause cancer in large amounts
Sudan IV is an animal mutagen and a potential carcinogen. It must never be handled by staff who are pregnant. It is highly toxic by the intravenous route but has not been quantified through other routes. It is an eye and respiratory tract irritant.
Come to the front teacher test for the results.

23. Sudan IV turns fats red Can you tell where the fat and where the water is in this test tube?
See the redder area on top in the right test tube. That is the cream floating on top.

24. Does milk have lipids? Does butter?
Added Sudan IV
Look for red color for (+) test

25. Is this a positive or negative fat test?
Before After drying
Positive
You are looking for translucence: light being able to show through paper.

26. We will use a paper towel divided into nine sections to test for fats.
Potato
Ultra Soy
Unknown A
Onion
Distilled Water
Unknown B
cream
Oil
Unknown C

27. Would this cat make a positive fat test?

28. What color is Biuret’s at start
What color is Biuret’s at start? How do you know if your sample is positive for protein?

29. PROTEIN TEST DO NOT HEAT PROTEIN TEST
Will turn from blue to purple on its own

30. Does milk have protein?
Added Biuret’s

31. SUMMARY OF MACROMOLECULE LAB TESTS