Question

You are given five test tubes containing purified biological macromolecules. The test tubes are unlabeled except for a number between 1 and 4. You are told that one test tube contains a protein, one contains a lipid, one contains a carbohydrate, and one contains a nucleic acid. You then perform some tests on the macromolecules and collect the following information that needs to be matched the type of macromolecule it most likely is in the tube.

1) Test tubes #2 and #4 contain nitrogen, but the other tubes do not.

2) The contents of test tube #3 are not soluble in water, but the contents of the other test tubes are soluble in water.

3) The contents of test tube #1 can be broken down into subunits that are all exactly identical to each other.

4) The macromolecule in test tube #2 is found to have a globular shape and turned purple during biuret test.

5. The macromolecule in test tube #5 tuned black when exposed to iodine.

What are the identities of the macromolecules present in the four test tubes? Find the Correct Matches

Test tube #1

      [ Choose ]            contains a lipid            contains a nucleic acid            contains a starch            contains a carbohydrate            contains a protein      

Test tube #2

      [ Choose ]            contains a lipid            contains a nucleic acid            contains a starch            contains a carbohydrate            contains a protein      

Test Tube # 3

      [ Choose ]            contains a lipid            contains a nucleic acid            contains a starch            contains a carbohydrate            contains a protein      

Test tube #4

      [ Choose ]            contains a lipid            contains a nucleic acid            contains a starch            contains a carbohydrate            contains a protein      

Test tube #5

      [ Choose ]            contains a lipid            contains a nucleic acid            contains a starch            contains a carbohydrate            contains a protein      

Answer 1

Test tube 1 contains a carbohydrate.

Undergoing break down, the produced similar components are called monomers of a polysaccharide.

Test tube 2 contains a protein; contains nitrogen.

Proteins react with Biuret reagent to give a purple colour of the product Biuret.

Test tube 3 contains a lipid.

Lipid is insoluble in water.

Test tube 4 is a nucleic acid and contains nitrogen.

Test tube 5 contains a starch.

On reaction with iodine starch produces a black colour. The hydrolysed products of starch gives this colour.