Biological Molecules Tests

Question 1

What is the test for starch?

Answer 1

1. Crush grind sample
2. Add iodine solution
3. Look for colour change from yellow brown to blue black

Question 2

What is the reducing sugars test?

Answer 2

1. Crush or find sample
2. Add distilled water
3. Add Benedicts solution
4. Place in water bath at 90 degrees for 5 minutes
5. Colour change from blue to brick red precipitate

Question 3

What is the test for non reducing sugars?

Answer 3

Test for reducing sugars to ensure none are present which may invalidate the result.

1. Crush or grind sample
2. Add distilled water
3. Add HCL
4. Place in water bath for a few mins to hydrolyse sample
5. Add sodium hydrogen carbonate to neutralise the sample
6. Add benedicts solution
7. Replace into water bath for a few more mins
8. Observe colour change from blue to brick red precipitate

Question 4

What is the test for lipids?

Answer 4

1. Crush or grind sample
2. Add ethanol
3. Add distilled water
4. Cloudy white emulsion indicates a positive test for lipids

Question 5

What is the test for proteins?

Answer 5

1. Crush or grind sample
2. Add biurets solution
3. Colour change from blue to purple