Macromolecules
At the end of this lab, students should know...
What does the term "Macromolecules" mean?
The term “macromolecules” means “large molecules”.
What are the four kinds of biological macromolecules?
The four kinds of biological macromolecules are: carbohydrates, proteins, lipids, and nucleic acids.
What are the functions of carbohydrates?
Some carbohydrates can be us...
- Solution Preparation
- CAUTION: It is important to always use care when handling reagents. For example, iodine will stain clothes and skin so wear gloves, goggles, and a lab coat when using this reagent.
- To prepare a 1 M glucose solution, begin by using a stir bar to dissolve 180.2 g of glucose in 500 mL of distilled water, increasing the volume to 1 L once the solute has dissolved in the smaller volume of solvent.
- To prepare a 10% cornstarch solution, first use a hotplate to boil 1 L of distilled water.
- Then make a paste with 8 g of cornstarch and 10 mL of cold water.
- Now, dissolve the cornstarch paste into the boiling water.
- To prepare a 10% gelatin solution, combine 1 g of gelatin powder with 1 L of distilled water.
- Then, use the hotplate to boil the solution until the gelatin has fully dissolved, taking care not to burn it.
- Beaker Labeling
- Label four beakers with the appropriate source material name and a corresponding image of the material.
- To Beaker A add an “A: Entire Corn Plant” label and image and fill the beaker with 250 mL of the glucose solution.
- To Beaker B add a “B: Corn Kernel” label and image and fill the beaker with 250 mL of the cornstarch solution.
- To Beaker C add a “C: Bone” label and image and fill the beaker with 250 mL of the gelatin solution.
- To Beaker D add a “D: Soybean” label and image and fill the beaker with 250 mL of vegetable oil.
- Then, cover the beakers with laboratory film until the activity begins.
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Q1: How do you prepare a 1 M glucose solution in the lab?
Dissolve 180.2 g of glucose in 500 mL of distilled water using a stir bar. Once the solute has dissolved in the smaller volume of solvent, increase the total volume to 1 L. This creates a 1 M glucose solution suitable for macromolecules identification using indicator solutions.
Q2: What is the proper procedure for making a 10% cornstarch solution?
Boil 1 L of distilled water on a hotplate. Make a paste by mixing 8 g of cornstarch with 10 mL of cold water. Dissolve the cornstarch paste into the boiling water, stirring until fully incorporated. This produces a 10% cornstarch solution for experimental use.
Q3: How should you prepare a 10% gelatin solution without burning it?
Combine 1 g of gelatin powder with 1 L of distilled water. Use a hotplate to boil the solution, monitoring carefully to prevent burning. Continue heating until the gelatin has completely dissolved, creating a uniform 10% gelatin solution for your macromolecule experiment.
Q4: Why is proper labeling important when preparing beakers for macromolecule experiments?
Labeling beakers with source material names and corresponding images ensures accurate identification of each solution throughout the experiment. Clear labels prevent cross-contamination and experimental errors, allowing students to track which macromolecule source is in each beaker during testing and analysis.
Q5: What safety precautions should you take when handling reagents like iodine?
Always wear gloves, goggles, and a lab coat when handling reagents such as iodine, which can stain clothes and skin. These protective measures minimize exposure to potentially harmful chemicals and prevent contamination of your workspace, clothing, and personal items during lab work.
Q6: How should prepared beaker solutions be stored before the experiment begins?
After filling each beaker with its designated solution—250 mL of glucose, cornstarch, gelatin, or vegetable oil—cover all beakers with laboratory film. This prevents contamination, evaporation, and oxidation of the solutions until the activity is ready to commence and testing begins.
Q7: What macromolecules do the different beaker solutions represent in this experiment?
Beaker A contains glucose solution representing carbohydrates from the entire corn plant. Beaker B holds cornstarch solution representing stored carbohydrates in the corn kernel. Beaker C contains gelatin solution representing proteins from bone. Beaker D holds vegetable oil representing lipids from soybeans.