Question

Procedure: Food groups Observation Inference Iodine test Test for starch i. Add 2mL of iodine solution to the 1% starch solution in a test tube. ii. Heat the above solution after making observation in step i. Test for lipids Add 2mL of oil to 2mL of water in a test tube. Add a few drops of Sudan III and shake it. Biuret test Test for proteins Add 2mL of protein solution (which is an extract of pulses, egg albumin, or milk) and 2mL of Biuret reagent.

Questions:

i. Name any two plant tissues that can be used to demonstrate the presence of protein.

ii. Identify one confirmatory test for the protein.

iii. Write any two precautions that you will take while conducting the test for starch.

iv. Explain the significance of this experiment in our daily life.

v. Design another method to test for the presence of lipids in food.

Answer 1

Two plant tissues that can be used to demonstrate the presence of protein are seeds and leaves. One confirmatory test for proteins is the Biuret test. Precautions to take while conducting the test for starch are to ensure cleanliness and controlled heating. The experiment is significant as it helps us understand the presence of nutrients in our food. Another method to test for the presence of lipids in food is the Sudan III test.

Step-by-step explanation:

i. Two plant tissues that can be used to demonstrate the presence of protein are seeds and leaves. Proteins are generally abundant in seeds and are essential for the growth and development of new plants. Similarly, leaves contain chloroplasts which are responsible for photosynthesis and also contain proteins necessary for various cellular functions.

ii. One confirmatory test for proteins is the Biuret test. In this test, Biuret reagent is added to the protein solution, and a color change from blue to violet indicates the presence of proteins.

iii. Two precautions to take while conducting the test for starch are:

1. Ensure that the test tube and all the equipment used are clean and free from any contamination.
2. Use a controlled heat source while heating the solution, such as a water bath or a bunsen burner, to avoid excessive heating or boiling.

iv. The significance of this experiment in our daily life is that it helps us understand the presence of different nutrients in our food. By testing for carbohydrates, lipids, and proteins, we can determine the nutritional content of different foods and make informed choices about our diet.

v. Another method to test for the presence of lipids in food is the Sudan III test. In this test, a few drops of Sudan III dye are added to a mixture of oil and water. The dye dissolves in the lipids present in the oil and stains them red, indicating the presence of lipids.