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Learning Objectives

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 used for short- or longer-term energy storage, while others are used to provide structure to cells.

What are proteins?

Proteins are composed of chains of amino acids. They function as enzymes, hormones, transport molecules, structural components and play vital roles in muscle contractibility, immunity, and blood clotting.

What is the most common type of lipid?

Triglycerides are the most common type of lipids, which include fats and oils. Triglycerides generally serve as long-term energy storage molecules.

List of Materials

  • Test Tubes
  • Disposable Pipets
  • Test tube racks
  • Beakers
  • 10 % Dextrose/Glucose, granular (5 mL/group)
    25 mL
  • 10 % Corn Starch soln (5 mL/group)
    25 mL
  • 10 % Gelatin soln (5 mL/group)
    25 mL
  • Vegetable Oil (5 mL/group)
    25 mL
  • Benedict's Solution (3 mL/group)
    15 mL
  • Iodine-Potassium-Iodide Solution (2 mL/group)
    10 mL
  • Sudan IV (0.5-1 mL/group)
    5 mL
  • Biuret Reagent (2 mL/group)
    10 mL
  • Parafilm sheet
    Dependent on the lab size
  • Hot plate
    Dependent on the lab size
  • Stirring bar
    Dependent on the lab size
  • Weighing scale
    Dependent on the lab size
  • Magnetic stirrer
    Dependent on the lab size

Lab Prep

  1. 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.
  2. 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.


JoVE Lab Lab: 18 Prep

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