In human digestion, what characteristic of plant material most commonly makes it more difficult to digest than animal tissue?

• A. High glycogen content, which resists digestion by human amylases
• B. High cellulose content in plant cell walls, which humans cannot enzymatically break down
• C. High starch content, which cannot be hydrolyzed in the small intestine
• D. High triglyceride content, which cannot be emulsified by bile

Answer: (B)

Verified step by step guidance

1. Identify the main components of plant material and animal tissue relevant to digestion, focusing on carbohydrates, proteins, and lipids.
2. Understand that human digestive enzymes can break down starch and glycogen, which are polysaccharides found in plants and animals respectively, but cannot break down cellulose.
3. Recognize that cellulose is a major component of plant cell walls and is a polysaccharide composed of glucose units linked by beta-1,4-glycosidic bonds, which human enzymes cannot hydrolyze.
4. Note that the inability to digest cellulose makes plant material more difficult to digest compared to animal tissue, which lacks cellulose and contains glycogen instead.
5. Conclude that the high cellulose content in plant cell walls is the characteristic that most commonly makes plant material harder to digest for humans.