Fehling Solution and Starch Test Experiment

Tests for Biomolecules

• Test for Sucrose: Add a small amount of Benedicts solution to a test tube, then add a few drops of sugar solution. Heat the mixture, and a red or orange precipitate will form, indicating the presence of sucrose.

• Test for Glucose: Mix 5cc of grape juice with 2cc of Fehling's solution in a test tube. Heat the mixture, and a red or orange precipitate will form, indicating the presence of glucose.

• Test for Starch: Mix a small amount of starch (e.g., from potatoes, rice, or wheat) with water to create a paste. Add a few drops of iodine solution, and a blue color will appear, indicating the presence of starch.

Protein Tests

• Xanthoproteic Test: Add a small amount of concentrated nitric acid to a test tube, and a white color will appear. Heat the mixture, and a yellow color will form. Then, add ammonia and heat again, and the color will change to orange, indicating the presence of protein.

• Biuret Test: Mix a small amount of sodium hydroxide and copper sulfate solution with a protein sample. Heat the mixture, and a purple color will appear, indicating the presence of protein.

• Millon's Test: Add a small amount of mercuric sulfate and nitric acid to a test tube, then add a few drops of protein solution. Heat the mixture, and a red color will appear, indicating the presence of protein.

Fat and Oil Tests

• Sudan III Test: Mix a small amount of fat or oil with Sudan III solution. A red color will appear, indicating the presence of fat or oil.

• Millon's Test: Add a small amount of mercuric sulfate and nitric acid to a test tube, then add a few drops of fat or oil. Heat the mixture, and a red color will appear, indicating the presence of fat or oil.

Preparation of Acetone Extract of Leaves

• Grind 10g of fresh spinach leaves with 40ml of 80% acetone and a small amount of calcium carbonate. Filter the mixture, and the resulting dark-colored liquid is the acetone extract of leaves, which contains chloroplast pigments.

Importance of Biomolecules

• Carbohydrates, fats, and proteins are essential biomolecules for the human body.

• Carbohydrates and fats provide energy for the body.

• Proteins are essential for the growth and repair of cells.

This quiz covers conducting an experiment with Fehling solution to test for the presence of glucose, and performing the starch test to identify the presence of starch using a simple experiment with a food sample. Learn about the procedures and expected results for each test.