Gizmo: Ch 2.3 Identifying Nutrients Name ______

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

  1. What are the 4 major types of macromolecules that you can get from food?

______

______

  1. Explain the important functions of each type of macromolecule:

Type / Functions

Have you ever wondered what is in your food? Scientists

use a variety of tests to determine the nutritional content

of food. You will learn 4 of those tests with the Identifying Nutrients Gizmo™.

Activity A:
Identifying nutrients / Get the Gizmo ready:
  • Click Reset.
  • Drag Sample A into the Food sample holder.
/

Tests for carbohydrates, proteins, and lipids

  1. Benedict Test is a test for monosaccharides (simple sugars) such as glucose or fructose (fruit sugar). In contact with monosaccharides, the Benedict solution turns from blue to pink.

Does Sample A contain monosaccharides? ______

  1. Lugol Test uses iodine to test for starch, apolysaccharide (complex sugar). Iodine turns dark purple in the presence of starch.

Does Sample A contain starch? ______

  1. Biuret Test uses a solution of potassium hydroxide (KOH) and copper sulfate (CuSO4) to test for protein. The Biuret solution turns purple when proteins are present.

Does Sample A contain proteins? ______

  1. Sudan RedTest uses a fat-soluble dye to indicate the presence of lipids. When lipids are present, the dye will be absorbed into the lipids, and will appear as concentrated spots of color in the test tube. (No spots indicates that lipids are not present.)

Does Sample A contain lipids? ______

  1. According to the 4 tests, what nutrients does Sample A contain? ______
  1. What kind of food is Sample A most likely to be? (Circle your choice)

A. Apple Juice B. Baked beans C. Chicken D. Scrambled Eggs

Test each food sample to determine the nutritional content

Activity B:
Nutrients and food types / Get the Gizmo ready:
  • Click Reset.
/

9. Use the 4 available tests to find the nutritional content of samples E, K, and R.

(Sample A has been done for you as an example) Record results on table below:

Carbohydrate Tests / Protein Test / Lipids Test / Test results – are these nutrients present?
Food Sample / Benedict Test / Lugol Test / Biuret Test / Sudan Red Test / Mono-saccharides / Starches / Proteins / Lipids
A / + / – / – / – / Yes / No / No / No
E
K
R

10. Is Sample E most likely steak, bread, or carrots? EXPLAIN YOUR ANSWER!

______

11. Is Sample K most likely sugar, nuts, or oil? EXPLAIN YOUR ANSWER!

______

12. Is Sample R most likely potatoes, cheese, or oranges? EXPLAIN ANSWER!

______

13. Determine the nutritional content of the remaining food samples:

Carbohydrate Tests / Protein Test / Lipids Test / Test results – are these nutrients present?
Food Sample / Benedict Test / Lugol Test / Biuret Test / Sudan Red Test / Mono-saccharides / Starches / Proteins / Lipids
B
C
D
F
G
H
I
J
L
M
N
O
P
Q
S

14. Why is it important to understand the nutritional content of food?

______

______

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