Testing for Biomolecules in Foods

Maya is conducting an experiment in her school laboratory to test for the presence of proteins in a food sample. Which indicator should she use?

• Iodine solution

• Biuret solution

• Benedict's solution

• Sudan III

Answer explanation

The Biuret solution is specifically used to test for proteins. It reacts with peptide bonds, turning from blue to purple in the presence of proteins, making it the correct choice for this test.

During a science experiment, Scarlett added iodine solution to a food sample. What color change indicates the presence of starch?

• Blue-black

• Red

• Green

• Orange

Answer explanation

The presence of starch in a food sample is indicated by a color change to blue-black when iodine solution is added. This reaction is a classic test for starch, distinguishing it from other substances.

Charlotte wants to test a food sample for lipids using the paper test method. Describe the procedure she should follow.

• Add iodine solution and look for a color change.

• Rub the food on a piece of paper and check for a translucent spot.

• Mix the food with Biuret solution and observe any color change.

• Heat the food sample and observe any changes.

Answer explanation

The correct method for testing lipids involves rubbing the food on paper. If lipids are present, a translucent spot will appear, indicating the presence of fats. This distinguishes it from other tests that do not specifically identify lipids.

Nora is conducting an experiment in her school laboratory to test for the presence of reducing sugars in a food sample. Which of the following tests should she use?

• Biuret test

• Iodine test

• Benedict's test

• Sudan III test

Answer explanation

Benedict's test is specifically designed to detect reducing sugars, such as glucose and fructose, in food samples. The other tests listed serve different purposes: Biuret for proteins, iodine for starch, and Sudan III for lipids.

Tags

NGSS.HS-PS1-2

Aria is conducting an experiment in her biology class to identify the presence of proteins in a sample. She decides to use the Biuret test. Explain why the Biuret test is used to identify proteins and what color change indicates a positive result.

• It reacts with lipids, turning red.

• It reacts with peptide bonds, turning purple.

• It reacts with starch, turning blue-black.

• It reacts with sugars, turning green.

Answer explanation

The Biuret test identifies proteins by reacting with peptide bonds, which are present in proteins. A positive result is indicated by a color change to purple, confirming the presence of proteins.

Emma is performing a test to detect the presence of starch in a food sample. Which of the following solutions should she use?

• Sudan III

• Benedict's solution

• Iodine solution

• Biuret solution

Lucas wants to confirm the presence of lipids in a food sample. Which test will provide a translucent spot as an indicator?

• Biuret test

• Iodine test

• Paper test

• Benedict's test

Olivia is using Benedict's solution in her experiment. What type of biomolecule is she testing for?

• Reducing sugars

• Lipids

• Starch

• Proteins

Isabella is testing a food sample for the presence of starch. Which color change should she look for after adding iodine solution?

• Blue-black

• Yellow

• Red

• Green

Henry wants to identify the presence of reducing sugars in a food sample. Which test should he perform?

• Sudan III test

• Iodine test

• Benedict's test

• Biuret test