1. Starter What is the function of the digestive system?
What are the main nutrients the body needs?
Why does the body need each nutrient?

2. L2: Food Tests Learning Objectives:
Recall nutrients needed by the human body.
Required Practical 3: Use qualitative reagents to test for a range of carbohydrates, lipids, and proteins.

3. Vocabulary List
Nutrient
Carbohydrate
Protein
Lipid

4. Vocabulary List Nutrient = molecules from food needed to survive
Carbohydrate = starch and sugar, nutrient used to obtain glucose for respiration, releasing energy
Protein = long chain of amino acids, nutrient used for growth and repair
Lipid = fat, nutrient used variety of functions

5. Required Practical 3: Food Tests
Use qualitative reagents to test for a range of carbohydrates, lipids and proteins.
Vocabulary
Qualitative
Quantitative

6. Required Practical 3: Food Tests
Use qualitative reagents to test for a range of carbohydrates, lipids and proteins.
Vocabulary
Qualitative – results NOT using numbers
Quantitative – results using numbers (quantities)

7. Required Practical 3: Food Tests
Read over the method and draw an appropriate results table.
Safety
Wear goggles and handle all chemicals carefully.
Iodine (IRRITANT), stains skin
Benedicts solution (IRRITANT)
Biuret reagent (IRRITANT, CORROSIVE)
Sudan III stain solution (HIGLY FLAMMABLE)

8. Title: GCSE Required Practical 3 – Food Tests Purpose: To test a variety of foods for the presence of the following nutrients a) carbohydrate (starch), b) carbohydrate (glucose), c) protein, and d) lipid (fat) Results: Conclusion: Our results show that the following nutrients are in each food:
Food
Starch Test
Glucose Test
Protein Test
Lipid Test
Bread
Egg White
Oil
Sugar Solution

9. Food Test Summary Test for starch (carbohydrate) Test for protein
Add iodine, if starch is present colour change orange  black
Test for protein
Add Biuret solution, if protein present colour change blue  purple
Test for glucose (sugar, carbohydrate)
Add Benedicts solution and heat in a water bath, if glucose is present colour change blue  green, orange, or brick red depending on amount of glucose
Test for lipid
Add ethanol and shake, if lipid present a milky white layer will form on top

10. Homework
Revise material (especially vocabulary and the required practical) for test coming up 10th November.