PRACTICALS MUST KNOW

Question 1

Emulsion test for lipids

Answer 1

Add sample to solution with equal parts ethanol and water. Shake vigorously for 20s.
If white emulsion forms, lipids are present. If no white emulsion forms, lipids are not present.

Question 2

Biuret test for proteins

Answer 2

Add sample to test tube. Add equal parts SODIUM HYDROXIDE SOLUTION and COPPER (II) SULFATE SOLUTION.
If solution turns purple, proteins are present. If solution stays blue, proteins are not present.

Question 3

Iodine test for starch

Answer 3

Add sample to test tube. Add IODINE dissolved in POTASSIUM IODIDE solution to sample.
If solution turns to dark blue/black then starch is present. If solution stays browny-orange then no starch is present.