Macromolecules Lab Reflection

In a lab that I completed in biology, I tested for four macromolecules, in a onion while other groups tested for these same macromolecules in other substances.  These four macromolecules were proteins, glucose, starch, and lipids.  To test for each one we used different reagent tests to show if the macromolecules were present or not.  For testing for proteins we used a bright blue biuret solution.  Since the solution turned brown when it was combined with the onion, that meant that there was a presence of proteins.  With the benedict solution, there was glucose if the solution turned a green to orange color.  In the linked picture you can see an example of the color change.  We used a lugols iodine solution to detect starch and rubbed the onion on brown paper to detect lipids.  Me and my partner determined that onions do contain protein and glucose, but starch and lipid macromolecules are not present.  I liked this lab because it was fun preforming each test and seeing if the macromolecules are present or not. Although, these results were a little different from the predictions that we made, I think they were accurate for the most part.  Some of the results to other people's substances surprised me.  For instance, I thought that the lemon would probably have at least one of the four but it ended up having none.  Some were obvious like it was apparent that the strawberry would have glucose because it is sugary and a that potato would have starch.