1 - Biochemical tests

Question 1

Test for starch?

Answer 1

• Add potassium iodide
• Positive turns orange to blue/black

Question 2

Test for reducing sugars?

Answer 2

1) Add Benedict’s and heat
2) Positive turns to blue to green, yellow, orange or brick red

Question 3

Test for non-reducing sugar?

Answer 3

1) View negative Benedict’s which stays blue

2) Add acid and boil

3) Cool solution and add alkali to neutralise

4) Positive test goes to blue to green, yellow, orange and brick red

Question 4

Name reducing sugar

Answer 4

Glucose, fructose, galactose, lactose, maltose

Question 5

Name non-reducing sugar

Answer 5

Sucrose

Question 6

What’s the test for proteins?

Answer 6

1) Add biuret
2) Blue to purple