ClE 9700 - Topic 2.1 - Past Paper MCQS

Which carbohydrate would form a brick-red solution when heated gently with Benedict's solution?

• A. Sucrose
• B. Cellulose
• C. Starch
• D. Glucose

Which of the following biological molecules would not form a purple colour when added to biuret solution?

• A. Amylase
• B. Amylose
• C. Haemoglobin
• D. Lipase

Which of the following sequences correctly shows the colour change in precipitates formed when a solution with a high concentration of reducing sugar is heated with Benedict's solution?

• A. Blue → yellow → orange - green → brick-red
• B. Blue → green → yellow → orange → brick-red
• C. Blue → brick-red - green → yellow → orange
• D. Green → blue → yellow → orange → brick-red

The diagram below shows a biological molecule. Which of the following tests would give a positive result for this molecule?

• A. Mixing with Biuret solution
• B. Heating gently with Benedict's solution
• C. Shaking with ethanol then pouring into water
• D. Adding iodine in potassium iodide solution

A sample of food was blended and several drops were decanted into a test tube with an equal volume of ethanol solution. The test tube was shaken vigorously for a minute before the mixture was poured into a test tube of water. A milky emulsion was observed. Which of the following biological molecules must have been present in the food?

• A. Carbohydrates
• B. Lipids
• C. Proteins
• D. Reducing sugars

Which of the following steps would not be involved in testing a sample for the presence of a non-reducing sugar?

• A. Mixing with copper (Il) sulfate
• B. Heating with copper (Il) sulfate
• C. Acid hydrolysis
• D. Neutralisation

Samples of a mixture of biological molecules underwent a series of biological tests. When the biuret test was carried out on a sample of the mixture, the mixture turned lilac. When iodine in potassium iodide was added to a sample, the mixture turned black. Which biological molecules were present in the mixture?

• A. Cellulose and phospholipid
• B. Starch and amylase
• C. Phospholipid and starch
• D. Cellulose and starch

The diagram below shows a biological molecule. Which of the following tests would give a positive result for this molecule?

• A. Heating gently with Benedict's solution
• B. Mixing with solutions of sodium hydroxide and copper (Il) sulfate
• C. Shaking with ethanol then pouring into water
• D. Adding iodine in potassium iodide solution

Which carbohydrate would test positive for the Benedict's test after acid hydrolysis, but negative before acid hydrolysis, has occurred?

• A. Sucrose
• B. Galactose
• C. Fructose
• D. Glucose

The diagram below shows part of a biological molecule. Which of the following tests would give a positive result for this molecule?

• A. Heating gently with Benedict's solution
• B. Mixing with solutions of sodium hydroxide and copper (Il) sulfate
• C. Shaking with ethanol then pouring into water
• D. Adding iodine in potassium iodide solution