virtual lab - biomolecules

Name _________________________________________________Date_______________Period________Deak #______

Identifying Biomolecules in Food – Guided Virtual Lab 1. Log on to the computer, and go to brscience.weebly.com  Biology Links  Biomolecules Virtual Lab 2. Read the page titled “Organic Molecules.” 3. What three substances are you going to learn to test for in foods? a. b. c.

Part I: Carbohydrates 4.

Click on the link near the bottom of the page titled “Carbohydrates.”

5. What does Benedict’s solution test for?

6.

Click on the blue link that says “Click here to fill a test tube with 2 mL of water.”

7. Using the information on this page, fill out the table below:

Bendict’s Reagent is normally:

Benedict’s Reagent after heating:

Benedict’s Reagent when sugar is present:

Color

8.

Continue following the directions on each screen and reading the pages to answer the following questions.

9. What happened to the Benedict’s solution when you heated it?

10. What happened to the mixture of Benedict’s solution and glucose when you heated it?

11. Fill in the following table for Benedict’s Solution: Positive for Simple Sugars

Negative for Simple Sugars

Color

12. What color results from mixing iodine and water?

13. What color results when you mix iodine and starch?

14. Fill out the following table for Iodine: Positive for Starch

Negative for Starch

Color

Part II: Proteins 15. Click on the tab labeled “Proteins.” 16. What indicator reacts with proteins?

17. What color biuret reagent turn when it reacts with proteins?

18. Begin the experiment by clicking on the blue link.

19. What happens when you add biuret agent to water?

20. What happens when you add biuret reagent to the sample of proteins?

21. Fill out the following table for testing for protein with Biuret reagent: Positive for Protein

Color

Part III: Fats (Lipids) 22. What is Sudan IV?

Negative for Protein

23. Click on the blue link to begin the experiment. 24. What happened when you added Sudan IV to the bottle of oil?

25. Fill out the following table for testing for lipids with Sudan IV: Positive for Lipids

Negative for Lipids

Color

Part IV: Testing Foods For this part of the lab, you will click on “Foods”, then record the results of each of the experiments for each type of food in the table below. For each of the boxes below, write a “+” if the food is positive for that type of biomolecule , or write a “-“ if the food is negative for that type of biomolecules. (Strong HINT: you may need to look back at your tables from earlier in the lab to see what the colors mean!). It may help you to write the color down in the blank first, then go back and write down the + or – sign later.

Biomolecule

Tested with

Simple Sugars

Benedict’s Reagent

Starch

Iodine

Protein

Biuret Reagent

Fat

Sudan IV

Potatoes

Orange Juice

Almonds

Eggs

Salmon (Fish)

Milk

Part V: Analysis Questions (you will probably need your notes)

1.

What is the function of carbohydrates? (Why do we need them?)

2.

What is at least one biological function of proteins?

3.

Which of the biomolecules that we tested for would help insulate animal tissue, helping animals to conserve heat?

4.

Which of the foods above would provide instant energy?

5. How is a simple sugar related to a starch?

6. What are the subunits of a protein?

7.

Many plants store