Which is a limitation of using cellulose
The correct answer and explanation is:
Correct Answer:
It is not easily digestible by humans.
Explanation (300 words):
Cellulose is a complex carbohydrate and a primary structural component of the cell walls in plants. It is made up of long chains of glucose molecules linked by β-1,4-glycosidic bonds. While cellulose serves many useful roles in nature and industry, it has a significant limitation when it comes to human digestion: our bodies cannot digest it.
Humans lack the enzyme cellulase, which is required to break the β-1,4 bonds in cellulose. As a result, when we consume plant-based foods containing cellulose (like vegetables and grains), the cellulose passes through our digestive system largely undigested. While this makes cellulose useful as dietary fiber, aiding in bowel movement and digestive health, it also means it cannot provide energy (calories) like starches or sugars do.
This limitation makes cellulose unsuitable as a nutritional carbohydrate source for humans. In contrast, animals like cows, goats, and termites harbor symbiotic bacteria in their digestive systems that produce cellulase, enabling them to break down and derive energy from cellulose.
Beyond digestion, cellulose has other limitations in industrial applications. For example:
- Poor solubility in water makes processing difficult.
- Mechanical weakness compared to synthetic fibers in some contexts.
- Susceptibility to microbial attack when not chemically modified.
Still, cellulose is widely used in paper, textiles (as rayon), and as a food additive or stabilizer. Despite these applications, its digestibility remains the primary biological limitation in human use.
In summary, although cellulose is abundant and useful, a key limitation is that it cannot be digested by humans, limiting its use as a direct food source and distinguishing it from other carbohydrates like starch.