1. Which of the following enzymes is responsible for the breakdown of carbohydrates into monosaccharides? A. Pepsin B. Lipase C. Amylase D. Protease Answer: C. Amylase Rationale: Amylase is the enzyme that catalyzes the hydrolysis of starch into sugars. In the digestive system, amylase is secreted by the salivary glands and the pancreas to break down dietary carbohydrates into simple sugars that can be absorbed. 2. What is the primary form of lipid digestion and where does it primarily occur? A. Emulsification in the stomach B. Hydrolysis in the mouth C. Emulsification in the small intestine D. Hydrolysis in the large intestine Answer: C. Emulsification in the small intestine Rationale: Lipids are primarily digested in the small intestine through the process of emulsification, which is facilitated by bile acids. This process breaks down large fat globules into smaller ones, increasing the surface area for enzymes to act upon. 3. During protein metabolism, amino acids that are not used for protein synthesis can be: A. Stored for future use B. Excreted as waste C. Converted into glucose or fat D. Used to synthesize DNA Answer: C. Converted into glucose or fat Rationale: Amino acids that are not needed for protein synthesis can undergo deamination, where the amino group is removed. The remaining carbon skeleton can be converted into glucose (gluconeogenesis) or fat for energy storage. 4. Which nutrient's metabolism involves the Krebs cycle and the electron transport chain?