Which food component is indigestible by the human body?

• A. Protein
• B. Glucose
• C. Cellulose (dietary fiber)
• D. Starch

Answer: (C)

Verified step by step guidance

1. Understand the question: The problem is asking which food component is indigestible by the human body. This requires knowledge of human digestion and the biochemical properties of the listed food components.
2. Review the components: Protein, glucose, cellulose (dietary fiber), and starch are all food components. Each has distinct properties and roles in human nutrition.
3. Analyze digestibility: Proteins are broken down into amino acids by enzymes like pepsin and trypsin. Glucose is a simple sugar that is readily absorbed by the body. Starch is a polysaccharide that is broken down into glucose by enzymes like amylase.
4. Focus on cellulose: Cellulose is a polysaccharide found in plant cell walls. Humans lack the enzyme cellulase, which is required to break down cellulose into glucose. Therefore, cellulose passes through the digestive system undigested, contributing to dietary fiber.
5. Conclude: Based on the analysis, cellulose (dietary fiber) is the food component that is indigestible by the human body.