Describe the procedure, observation, and explanation for testing proteins in non-germinating maize seeds using the Biuret test.

Here is the procedure, observation/result, and explanation for the protein test using the filtrate from non-germinating maize seeds:

B. Test for Proteins

Procedure:

1. Crush five non-germinating maize seeds in a mortar using a pestle.
2. Add approximately 10 ml of distilled water to the crushed maize seeds in the mortar and stir thoroughly.
3. Filter the mixture using a filter funnel and filter paper into a clean test tube or beaker to obtain the maize seed filtrate.
4. Pour about 2 ml of the obtained filtrate into a clean test tube.
5. Add 2 ml of sodium hydroxide solution (NaOH) to the test tube and shake gently.
6. Carefully add 2-3 drops of copper(II) sulfate solution (CuSO$_{4}$) to the test tube.
7. Gently shake the test tube and observe any color change.

Observation / Result:

• The maize seed filtrate turns violet or purple upon the addition of sodium hydroxide and copper(II) sulfate solutions.

Explanation of results:

• The Biuret test is used to detect the presence of proteins.
• Proteins are composed of amino acids linked by peptide bonds.
• In the presence of an alkaline solution (sodium hydroxide), copper(II) ions from copper(II) sulfate react with the peptide bonds in proteins to form a violet-colored complex.
• Non-germinating maize seeds contain proteins, particularly in the embryo and to a lesser extent in the endosperm, which serve as food reserves.
• The violet color change observed indicates a positive test for proteins, confirming their presence in the non-germinating maize seed filtrate.