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Student Exploration: Identifying Nutrients

Directions: Follow the instructions to go through the simulation. Respond to the questions and
prompts in the orange boxes.

Vocabulary: carbohydrate, disaccharide, lipid, monosaccharide, polysaccharide, protein, starch

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

1.​ What are the major types of nutrients you can get from food?

Starch, Monosaccharides, Protein, and Lipids

2.​ How are these nutrients used by your body?

Protein is used to strengthen muscles, Carbohydrates create energy, and Lipids are used to
create hormones and store energy

Gizmo Warm-up
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 four of
those tests with the Identifying Nutrients Gizmo.

1.​ Below the Food samples label, drag tube A into the Food sample
holder. Below the Benedict test, click the Test button. What is done
in the Benedict test?

Some of the solution is put into a test tube where it is

then heated.

2.​ The Benedict solution is a test for monosaccharides; simple sugars

like glucose or fructose (fruit sugar); and some disaccharides such
as lactose and maltose. In contact with these sugars, the Benedict
solution turns from blue to green to orange. For simplicity, we will
consider the Benedict test a test for monosaccharides only.

Does Sample A contain these sugars? Yes

Note: Sucrose (table sugar) is a disaccharide that is not detected by the Benedict test. Foods sweetened
only with table sugar will show a negative Benedict test.

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Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved ​
 Activity A: Get the Gizmo ready:

Identifying ●​ Click Reset.

nutrients ●​ Drag Sample A into the Food sample holder.

Introduction: Most food is composed of three types of molecules: carbohydrates, proteins, and lipids.
●​ Carbohydrates such as starches and sugars are major source of energy. Simple sugars are found in
sweets and fruits. Starches are found in potatoes, cereal, pasta, flour, and other plant products.
●​ Proteins are used in body structures such as muscles, skin, and hair. Rich sources of proteins include
meats, dairy products, and beans.
●​ Lipids (fats and oils) are used for energy, insulation, and as an essential building block of cells. Meats,
dairy products, and oily plants such as olives are rich in lipids.

Question: How do you test for carbohydrates, proteins, and lipids?

1.​ Test: Under the Benedict test, click Test.

Is the Benedict test positive for sample A? Yes
Recall that orange is a positive test for monosaccharides (and some disaccharides).

2.​ Test: The Lugol test uses iodine to test for starch, a polysaccharide (complex carbohydrate). Iodine turns
dark purple in the presence of starch.

Under Lugol test, click Test. Does sample A contain starch? No

3.​ Test: The 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.

Under Biuret test, click Test. Does sample A contain proteins? No

4.​ Test: The Sudan Red test uses a fat-soluble dye, Sudan Red, 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.)

Under Sudan Red test, click Test. Does sample A contain lipids? No

5.​ Summarize: What nutrients does sample A contain?

Monosaccharides

6.​ Analyze: What kind of food is sample A most likely to be? (Highlight the food type)

Apple juice Baked beans Oatmeal Scrambled eggs

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 Activity B:
Get the Gizmo ready:
Nutrients and ●​ Click Reset.
food types

Question: What nutrients does each food sample contain?

1.​ Collect data: Use the four available tests to find the nutritional content of samples E, G, and M. (Sample A
has been done for you as an example.) Record results on the table below.

Carbohydrate Protein Lipids

Test results – are these nutrients present?
Tests Test Test

Food Benedict Lugol Biuret Sudan Mono-

Starches Proteins Lipids
sample test test test Red test saccharides

A + – – – Yes No No No
E - - + + No No Yes Yes
G - - - - No No No No
M - +

2.​ Analyze: Look at the results for samples A, E, G, and M.

A.​ Is sample E most likely to be steak, bread, or butter? Justify your answer.

Steak, out of all those options, steak is the only one with protein.

B.​ Is sample G most likely to be table sugar, pasta, or olive oil? Justify your answer.

Table Sugar, since sucrose doesn’t show up on tests, we know that sample G is table
sugar

C.​ Is sample M most likely to be chicken, rice, a mango, or butter? Justify your answer.

Rice, because it is high in starches.

3.​ Draw conclusions: Why is it important to understand the nutritional content of food?

It allows you to balance your diet and be able to create proportions with what you eat.

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4.​ Practice: Determine the nutritional content of the remaining food samples.

Carbohydrate Protei Lipids

Test results – are these nutrients present?
Tests n Test Test

Food Benedict Lugol Biuret Sudan Mono-

Starches Proteins Lipids
sample test test test Red test saccharides

B - - + + No No Yes Yes
C - + - - No Yes No No
D - - + + No No Yes Yes
F - - - - No No No No
H - - + + No No Yes Yes
I + - - - Yes No No No
J – – + + No No Yes Yes
K + - - - Yes No No No
L - - + + No No Yes Yes
N - + - - No Yes No No
O - - - - No No No No
P + - - - Yes No No No
Q - - + + No No Yes Yes
R - + - - No Yes No No
S - - + + No No Yes Yes

5.​ Think and discuss: If possible, discuss these food samples with your classmates and teacher. Try to come
up with a type of food that corresponds to each sample.

6.​ Extend your thinking: In general, a balanced diet contains relatively even amounts of carbohydrates,
proteins, and lipids. Too much sugar is unhealthy. Fruits and vegetables are important sources of vitamins
and minerals.

Do you consider your diet balanced and healthy? Why or why not?

No, i eat a lot of sugars and not a lot of fruit or fat, I just eat chicken and gummies.

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