Macromolecule Lab

Our Goal

The overall macromolecule lab was two labs designed to use standard solutions to identify positive and negative controls of different indicators. Our goal was to learn about how macromolecules are essential to the survival and growth of living organisms and how they are the building blocks of the foods we eat.

Evidence of Work

The first lab was testing for 3 of the macromolecules, proteins, lipids, and carbohydrates, using different chemical indicators on standard solutions. We wanted to prove that we could identify a positive result of the specific macromolecule in each test.

The second part of the lab was testing for macromolecules in food that our group brought in. We brought in almonds and jam and because these are solid foods, we used a mortar and pestle to grind up and liquify the food. We tested for monosaccharides, starch, proteins, and lipids. We used our previous observations to compare positive and negative results.

Almond -

If we test almonds for macromolecules, then it would test positive for carbohydrates, proteins, and lipids. To complete our test, we followed the same lab setup and procedures as the Macromolecule Testing Standards lab, however we substituted in almond paste as the positive indicator in all the tests. This allowed us to see what macromolecules were contained within almonds. In the carbohydrate test, 2ml of almond paste and 2ml of Benedict’s solution were mixed and heated at 100 degrees Celsius for 2 mins. This tube turned a dark black color compared to the negative test tube (2ml of water instead of almond paste, present for all negative test tubes) that stayed a light blue. The starch test contained 2ml of almond paste and 0.1ml of Lugol’s iodine solution. The positive and negative tests both stayed a light orange color. The protein test was a combination of 2ml of almond paste and 0.75ml of Biuret reagent. In this test the positive tube immediately turned purple while the negative tube stayed light blue. The lipid test proved positive when the drop of almond on a paper towel allowed light through after 10 minutes while the drop of water did not. In the tests where the positive test tube showed a reaction different to the negative test tube, it shows that almonds contains that macromolecule. This experiment proved our hypothesis correct, almonds contains carbohydrates, lipids and proteins.

Jam -

If we test strawberry jam for macromolecules, then it would test positive for carbohydrates and lipids. To complete our test, we followed the same lab setup and procedures as the Macromolecule Testing Standards lab, however we substituted in a diluted strawberry jam as the positive indicator in all the tests. This allowed us to see what macromolecules were contained within strawberry jam. In the carbohydrate test, 2ml of diluted jam and 2ml of Benedict’s solution were mixed and heated at 100 degrees Celsius for 2 mins. This tube quickly turned a bright orange compared to the negative test tube (2ml of water instead of jam, present for all negative test tubes) that stayed a light blue. The starch test contained 2ml of diluted jam and 0.1ml of Lugol’s iodine solution. The positive and negative tests both stayed a light orange color. The protein test was a combination of 2ml of diluted jam and 0.75ml of Biuret reagent. In this test the positive tube turned a dark green and then yellow while the negative tube stayed light blue. The lipid test proved positive when the drop of diluted jam on a paper towel allowed light through after 10 minutes while the drop of water did not. In the tests where the positive test tube showed a reaction different to the negative test tube, it shows that strawberry jam contains that macromolecule. However I am not sure about the protein test because that reaction had not occurred in any of the previous tests in which we know there was protein. Overall this experiment proved our hypothesis correct, strawberry jam contains carbohydrates and lipids.

Content

Macromolecule -

A macromolecule is defined as a large, organic molecule that is necessary for life. Macromolecules are split into four groups: carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrate -

A macromolecule that is a main source of energy for all living things. The monomer of a carbohydrate is a monosaccharide or a simple sugar, built from 1 carbon atom, 2 hydrogen atoms, and 1 oxygen atom. You can find carbohydrates in any food, however they are prevalent in starches and sugars.

Lipid -

A macromolecule that is used for energy storage, protection and insulation of the cell, forming the cell membrane, and a chemical messenger. The monomer of a lipid is glycerol and fatty acids. Lipids can be located in oils, fats, and waxes.

Protein -

A macromolecule that is used for energy storage, transportation, regulation, the structure of the organism, and in enzymes. The monomer of protein is amino acids and protein can be found in nuts, beans, and meats.

Nucleic Acid -

A macromolecule that is used to carry the genetic information to make proteins. The monomer of Nucleic acids are nucleotides. Nucleic acids are present within DNA and RNA.

Monomer -

Monomers are defined as small molecules or atoms that bond together to create more complex structures, like polymers. The main four monomers are sugars, amino acids, fatty acids, and nucleotides.

Polymer -

Polymers are a long chain or network of repeating or identical monomers.

Characteristics of Life -

In order for an organism to be considered living, it needs to meet the characteristics of D.O.G.S.R.E.A.C.H.: DNA, Organization, Growth, Stimulus response, Reproduction, Energy, Adaption, Cells, and Homeostasis.

Positive and Negative Controls -

A positive control is the testing of a substance when you know that what you are testing for is present, and the test is completed to see a positive result. A negative control is the testing of a substance when you know that what you are testing for is not present and the test is completed to see a negative result.

Chemical Indicator -

Occurs when any substance gives a visible sign, usually a color change, or the presence or absence of a particular substance.

Reflection

Overall I think that this project went really well. Our group worked really well together and we worked very efficiently. I felt like I worked hard during this lab so I could fully understand the concepts we were working on. I was very focused and helpful to my group. With this, I think that I excelled in the Collaboration category of the 6 C's. I contributed to the success of my team, took ownership for my responsibilities within our work, and maintained a positive attitude. Another 6 C's component I think I demonstrated was being a contentious learner. To fit all of our testing and lab work into two days, our group had to work very efficiently and manage our time well. We also had challenges with the indicator but we faced these problems with a growth mindset and grew from it. One thing I felt I could have done better on was allowing another person to take the lead. Because we were under a time crunch, I took leadership of the group and led our group on the experiments. On the next lab I will try harder to allow everyone a chance to lead the group and earn the leadership experience.

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