GCSE Biology Food Tests Quiz

Which reagent is used to test for the presence of lipids in a food sample?

• Benedict's solution

• Ethanol

• Iodine solution

• Biuret reagent

Answer explanation

Ethanol is used to test for the presence of lipids in a food sample by dissolving the lipids, making them visible.

What colour change indicates the presence of starch when iodine solution is added?

• Blue to green

• Red to blue

• Brown to blue-black

• Yellow to red

Which reagent is used to test for the presence of glucose in a food sample?

• Biuret reagent

• Iodine solution

• Benedict's solution

• Ethanol

What is the initial colour of Benedict's solution before it is added to a sample?

• Blue

• Red

• Green

• Yellow

What colour change indicates the presence of proteins when Biuret reagent is added?

• Blue to purple

• Red to green

• Yellow to blue

• Brown to black

What is the first step in the lipid test using ethanol?

• Add iodine solution to the sample

• Heat the sample with Benedict's solution

• Mix the sample with ethanol and then add water

• Add Biuret reagent to the sample

What is the expected result if a food sample contains glucose after heating with Benedict's solution?

• The solution remains blue

• The solution turns orange-red (or brick-red)

• The solution turns purple

• The solution turns blue-black

Which of the following is NOT a step in the starch test?

• Add iodine solution to the sample

• Heat the sample with Benedict's solution

• Observe the colour change

• Use a white tile for better visibility

Answer explanation

Heating the sample with Benedict's solution is NOT a step in the starch test, making it the correct choice.

What is the purpose of the Biuret test in food analysis?

• To test for lipids

• To test for starch

• To test for glucose

• To test for proteins

What is the expected result if a food sample contains lipids after performing the ethanol test?

• A blue-black colour appears

• A purple colour appears

• A cloudy white emulsion forms

• The solution remains clear