b7 testing Flashcards
What is the method for testing starch?
Add a few drops of iodine solution to the substance.
Iodine will stain hands and materials.
What color change indicates a positive result for starch?
Orange to blue-black.
What is the method for testing lipids?
Add a few drops of ethanol to the substance, shake, and allow to stand for one minute. Pour the ethanol into a test tube of water.
Ethanol is flammable and harmful.
What color change indicates a positive result for lipids?
Colourless to cloudy.
What is the method for testing proteins?
Add a few drops of copper sulfate solution to the substance, then add a few drops of sodium hydroxide solution.
Copper sulfate is harmful, and sodium hydroxide (<0.5 mol/dm³) is an irritant.
What color change indicates a positive result for proteins?
Pale blue to purple.
What is the method for testing reducing sugars?
Add a few drops of Benedict’s solution to the substance, then heat the test tube in a water bath.
What color change indicates a positive result for reducing sugars?
Blue to orange-red.
True or False: Ethanol is safe to handle without precautions.
False.
Fill in the blank: A positive test for starch shows a color change from orange to _______.
blue-black.
Fill in the blank: A positive test for lipids shows a color change from colourless to _______.
cloudy.
Fill in the blank: A positive protein test results in a color change from pale blue to _______.
purple.
Fill in the blank: A positive reducing sugar test results in a color change from blue to _______.
orange-red.
What are the learning objectives of the B4 Enzymes lesson?
After studying this lesson you should be able to:
* Safely use appropriate heating devices and techniques
* Use appropriate apparatus and techniques for observation and measurement
* Measure rates of reaction by various methods.
What are biological washing powders designed to do?
Break down clothing stains caused by foods using enzymes.
What is the role of amylase in enzyme action?
Breaks down starches into glucose.
What does protease do?
Breaks down proteins into amino acids.
What is the function of lipase?
Breaks down fats into fatty acids and glycerol.
What factors can affect the rate of an enzyme-controlled reaction?
Temperature, pH, and enzyme and substrate concentrations.
Fill in the blank: Amylase digests starch into _______.
glucose
What is the first step in finding the optimum conditions for amylase to digest starch?
Select the factor you wish to investigate.
How should enzymes be used to avoid harmful dusts?
In liquid form.
What is a good practice when judging the end point of a reaction involving a color change?
Have an example of the end-point color for easy comparison.
