Identifying Nutrients: A Laboratory Exploration, Summaries of Organic Chemistry

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K. Export, J. Wilson,

Identifying nutrients

Name: Date:

Student Exploration: Identifying Nutrients

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

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?

2. The Benedict test is a test for monosaccharides ; simple sugars like glucose or fructose

(fruit sugar). In contact with monosaccharides, the Benedict solution turns from blue to

green to orange.

Does Sample A contain monosaccharides?

Note: Disaccharides such as sucrose (table sugar) and lactose (milk sugar) are more

complex than monosaccharides. The Benedict test does not detect disaccharides directly.

There are six major

nutrients: Carbohydrates (CHO), Lipids (fats), Proteins, Vitamins, Minerals, Water.

The body uses three main nutrients to function carbohydrate, protein, and fat. These nutrients are digested

into simpler compounds. Carbohydrates are used for energy (glucose). Fats are used for energy

after they are broken into fatty acids.

Solutions were added and it was heated in a water bath for f min

yes

Activity B:

Nutrients and

food types

Get the Gizmo ready:

• Click Reset.

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

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

G

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.

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

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

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

(Activity B continued on next page)

• no

no

yes yes

Steak because it has proteins and fats

no no no

no

no yes

no no

Sample G would be table sugar because we did not test for disaccharides and they don't show the test

results for proteins, carbohydrates or lipids.

Rice because it is a starch and food sample M tested positive for the Lugol test.

Every nutrient plays a role and is very important to our body. We have to know about nutrients so

that we can apply each one to out bodies in the correct form.

Activity B (continued from previous page)

4. Practice: 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 H I J K L N O P Q R S

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 (monosaccharides and other simple

sugars) 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 no yes

yes

no

yes no

no

no no yes yes

no no no no

no no yes yes

yes no no no

no no yes yes

yes no no no

no no yes yes

no yes no no

no no no no

yes no no no

no no yes yes

no yes no no

no no yes yes

I think my diet is balanced because it contains relatively even amounts of

carbohydrates, proteins, and lipids and I don't really eat that much sugar.