A mystery solution was tested using iodine. The mystery solution turned black while the control remained iodine-colored. What is this solution?
A complex carbohydrate, or polysaccharide, such as a starch or cellulose.
A biochemist wants to test five different mystery solutions for nutrients. In her experiment, what would be the controlled variables?
Each test tube would be the same size. Every test tube would get the same amount of liquid. Every test tube is exposed to the same temperature and reagent.
In an iodine test, what is the experiemental control?
A test tube with just iodine added and no mystery chemical. You will need this to compare the colors to determine if there was a postive reaction.
A biochemist is testing five different mystery solutions for protein. He designates one test tube for a control. What is his independent variable?
The mystery solutions since they will be the only variable that is different during the test.
A biochemist is testing five different mystery solutions for protein. He designates one test tube for a control. What is his dependent varaible?
What kind of reaction (or color change) happens after the chemical testing is complete.
Which Bennedict's test is positive?
The test tube on the left that turned orange.
What does a positive Bennedict's test tell you about the mystery solution you are testing?
If the Bennedict's solution turns orange, the mystery solution contains a monosaccharide or reducing sugar.
A Bennedict's test was performed. Is it possible that positive test reveals that the solution contains sucrose?
Nope. Sucrose is a disaccharide. A Bennedict's test can tell you if a monosaccharide (reducing sugar) is in the solution.
Starch and Celluose are both ______________.
Polysaccharides that turn black with an iodine test.
Iodine was added to bread. What does the result of the chemical reaction tell you?
The bread contains starch.
Which test tube has the positive Biuret test?
The test tube on the right that has turned dark purple has the positive Biuret test.
When Biuret solution is added to a mystery solution the chemical reaction produced a dark purple color. What does this tell you?
The mystery solution contains protein.
A biochemist is performing a Biuret test on a mystery solution. Which test tube would be the experimental control? Why is this needed.
The experimental control has just Biuret solution (and water) with no mystery solution added. This allows for comparison.
What does a positve Sudan III test tell you about a mystery solution?
That it contains lipids (fats).
If you really want to know if this Sudan III test of this mystery solution is postive, what should you do?
Compare it to a control in which Sudan III has been added to water but NOT added to the mystery solution.
