Biochemistry and Enzyme Function Assessment

Part A: Multiple Choice

• What is the monomer of a protein?
  Answer: c) Amino acid
• A scientist adds Lugol's iodine solution to an unknown clear liquid, and it instantly turns deep blue-black. What biomolecule is present?
  Answer: b) Starch
• Why does an enzyme cease to function after being exposed to an extremely high temperature?
  Answer: c) The enzyme denatures, altering the shape of its active site.
• Which of the following functions as a micronutrient in the human body?
  Answer: b) Iron (Mineral)

Part B: Structure Identification & Fill-in-the-Blanks

1. Peptide bond
2. Protein
3. Starch
4. Glycogen

Part C: Metabolic Roles and Protein Folding

While carbohydrates provide the raw chemical energy (calories) for the body, micronutrients (vitamins and minerals) act as essential cofactors and coenzymes that allow metabolic reactions to actually occur. For example, the mineral iron is crucial for hemoglobin to transport oxygen, and B-vitamins are required to convert glucose into usable cellular energy (ATP). Without these micronutrients, the metabolic machinery fails to process carbohydrates efficiently, resulting in severe fatigue.

A mutation alters the primary structure (the specific sequence of amino acids). Because the chemical properties of each amino acid determine how the chain folds, a single change can disrupt the hydrogen bonds, disulfide bridges, and hydrophobic interactions responsible for the secondary and tertiary structures. If the protein cannot fold into its correct complex 3D shape, it loses its structural integrity and ceases to function.

Part D: Experimental Design

Hypothesis: As temperature increases, the rate of the enzymatic reaction will increase until it reaches an optimal point; beyond this temperature, the reaction rate will drop sharply due to denaturation.

Variables:

• Independent Variable: The temperature of the enzyme solution.
• Dependent Variable: The rate of reaction, measured by the volume of oxygen gas produced per minute.
• Controlled Variables: Enzyme concentration (using identical amounts of catalase from potato extract), substrate concentration and volume (hydrogen peroxide), and the pH of the solution.