Macromolecule Testing Lab

Description:

1st Part:

Purpose: To use standard solutions to identify positive and negative controls of different indicators.

Testing For: Testing to look for a positive and negative control.

Below is the table showing what type of macromolecules we tested, an example of each one, and the indicator we used to test with them.

The four macromolecules we looked at were glucose, starch, gelatin and vegetable oil. We used Benedict's to test for glucose, iodine for starch, biurets for gelatin, and paper towels for vegetable oil.

For each macromolecule we did a certain test: one for a positive control (evidence of macromolecule) and one for a negative control (no evidence of the macromolecule). Below (left) is a photo of the procedures we did for each macromolecule, including how much of the indicators we put in the testing tube (measured in ml) and what we did to both substances (mix, heat, let sit, etc.). Below (right) is the table of data we collected, showing the standard molecule we used, indicator we used, and the positive and negative result.

Procedures

Data Table

Data Table: For each standard molecule we tested for, we got a positive and negative result. We could tell whether or not the macromolecule was present or not depending on which color the liquid became. Each macromolecules positive and negative test is explained more below:

  • Glucose: A negative test should turn blue (same color as benedicts) showing no monosaccharides are present. A positive test should turn a thick orange showing monosaccharides are present.

  • Starch: A negative test should turn clear orange showing no polysaccharides are present. A positive test should turn black showing polysaccharides are present.

  • Gelatin: A negative test should turn light blue showing no proteins are present. A positive test should turn dark blue or purple, showing proteins are present.

  • Vegetable Oil: A negative test should have the paper towel not be very transparent, showing less evidence of lipids. A positive test should have the paper towel turn more transparent showing lipids are present.

2nd Part:

The second part of this lab was for my group to test two foods and see what macromolecules were present in each. We did each of the same tests for apples and Nutter Butters but instead of using macromolecules and water, we used the food and the indicators. Based on the positive and negative results from the previous test we were able to tell what macromolecules were present or not in each food based on the color each tube turned. Below is our data table that shows the result.

Apple:

  • Small evidence of molysaccharides (tuned yellow)

  • Lots of evidence of polysaccharides (turned black)

  • Moderate evidence of proteins (tuned dark blue)

  • Moderate evidence of lipids (60% see through)

Nutter Butter:

  • Lots of evidence of molysaccharides (turned orange/red)

  • Small evidence of polysaccharides (turned yellow/orange)

  • Small evidence of proteins (mild blue)

  • Moderate evidence of lipids (50% see through)

Content:

Macromolecule: Smaller building blocks that make up cells and organelles. Four basic types of carbohydrates: lipids, proteins, carbohydrates and nucleic acids.

Lipids: Made up of fatty acids. They make up the cell membrane, which provides cell structure, keeps the body warm, and are used for long term energy storage. Found in meat/fish, oils, avocados, eggs and nuts.

Proteins: Made up of amino acids. They build and repair muscles. Found in meat/fish, legumes, nuts, milk eggs, grains and soy products.

Carbohydrates: Made up of simple sugars (monosaccharides) and complex carbohydrates (polysaccharides). Provide body with energy. Simple carbs are found in most candy, sweet drinks, fruit, veggies and milk. Complex carbs are found in pasta, bread, potatoes, legumes and corn.

Nucleic Acids: Made up of nucleotides (DNA or RNA: polymer). Stores and carries genetic information. Found in vitamins and minerals.

Reflection:

One thing for this lab that we could have done better was communication. Sometimes, in my group, we would tell each other the wrong information. Like the wrong indicator for a macromolecule or a wrong measurement of something. These silly mistakes caused us to have to redo a couple experiments and waste time. If we read the directions slower and tell each other the correct information we will not have to redo certain parts of the experiment. This would save us time and allow our group to be more efficient. Other than a few silly miscommunication errors our group did a good job completely the lab and understanding what we learned.

Something we did was cooperation. We all worked super well together and stayed on task most of the time. We each had our tasks and knew what to do, and when we needed to do it. Also, everyone kinda worked together very nice. We were still able to have fun while getting our task done, that is the best type of group and really made the experience better.