Biology Experiments OB11 Carry out qualitative tests to compare the carbon dioxide levels of inhaled and exhaled air. OB3 Qualitative food tests for starch, reducing sugar, protein and fat. Food Tested Procedure / Chemicals Used Positive Result Starch Add iodine blue-black Reducing sugar e.g. glucose Add Benedict’s solution and heat brick-red Fat Rub food on brown paper Translucent Stain Protein Add sodium hydroxide and then copper purple sulfate OB5 Investigate the conversion of chemical energy in food to heat energy. Procedure Pour water into a test-tube and note the temperature. Place a burning cream-cracker or peanut under the test-tube. Leave for a minute. Take the temperature of the again. Result The temperature of the water rises as a result of gaining energy from the burning peanut. OB8 Investigate the action of amylase on starch; identify the substrate, product and enzyme. Procedure: Add some saliva (which contains the amylase enzyme) to a starch solution which is in a test tube. Confirm beforehand that the substrate is starch by adding iodine to it it should turn blue/black. – Heat in a water bath at 37 0C for 10 minutes. The starch should now be converted to a simple sugar product called maltose so we need to test for this. Add some Benedict’s solution and place in boiling water for a few minutes. Result The contents of the test-tube should turn red, indicating that sugar is present. Procedure Suck air in through position A in Test tube A.
Biology Experiments OB3 Qualitative food tests for starch, reducing sugar, protein and fat. Food Tested Procedure / Chemicals Used Positive Result Starch Add iodine blue-black Reducing sugar e.g. glucose Add Benedict’s solution and heat brick-red Fat Rub food on brown paper Translucent Stain Protein Add sodium hydroxide and then copper sulfate purple OB5 Investigate the conversion of chemical energy in food to heat energy. Procedure Pour water into a test-tube and note the temperature. Place a burning cream-cracker or peanut under the test-tube. Leave for a minute. Take the temperature of the again. Result The temperature of the water rises as a result of gaining energy from the burning peanut. OB8 Investigate the action of amylase on starch; identify the substrate, product and enzyme. Procedure: Add some saliva (which contains the amylase enzyme) to a starch solution which is in a test tube. Confirm beforehand that the substrate is starch by adding iodine to it – it should turn blue/black. Heat in a water bath at 37 0C for 10 minutes. The starch should now be converted to a simple sugar product called maltose so we need to test for this. Add some Benedict’s solution and place in boiling water for a few minutes. Result The contents of the test-tube should turn red, indicating that sugar is present. OB11 Carry out qualitative tests to compare the carbon dioxide levels of inhaled and exhaled air. Procedure Suck air in through position A in Test tube A.
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