1. Food Tests
Lesson 9

2. Success Criteria
Describe how to carry out the chemical tests for biological molecules

3. Starter: Complete Table
Testing for
Description
Negative Result
Positive Results
Starch
Reducing Sugar
Non-reducing sugar
Protein
Lipid

4. Starter: Answers Testing for Description Negative Result
Positive Results
Starch
Add iodine
Brown
Blue/black
Reducing Sugar
Add Benedict’s
Heat to 80oC
Blue
Orange/Red
Non-reducing sugar
Negative to RS
Boil in acid
Neutralise
Protein
Add biuret reagent
Lilac
Lipid
Add ethanol
Add to water
Clear
White/Cloudy

5. Task
Practical Skills: Qualitative
Drawing Results Table
Identify the type of biological molecule contained within each of the 5 unknown samples:
Starch
Reducing sugar
Non-reducing sugar
Protein
Lipid
In your pairs decide first how you are going to approach the task, which tests will you carry out first?
How will you record your results?

6. Peer Assess Results Table
Mark
Complete?
Appropriate column and row headings
Ruled rows and columns
Separate conclusions and observation columns
All tests and results recorded
Correct conclusions for all test results

7. Success Criteria
Describe how to carry out the chemical tests for biological molecules

8. Plenary: ?/5
Assess your results table against the coursework mark scheme
all raw data presented in a single table with columns correctly labelled [1]
test recorded in column 1 [1]
all colours recorded to one/two word answers [1]
Ruled lines drawn, including around the outside [1]
Full headings in columns [1]

9. Homework
Answer questions on practical sheets