Which of the following is a structural polysaccharide ?

Options

A. Glycogen
B. Starch
C. Inulin
D. Cellulose

Answer

To determine which of the following is a structural polysaccharide, we need to analyze each option provided: glycogen, starch, inulin, and cellulose.

### Step-by-Step Solution:

1. **Understanding Polysaccharides**:
- Polysaccharides are large molecules made up of long chains of monosaccharide units. They can be classified into two categories: storage polysaccharides and structural polysaccharides.

2. **Analyzing Glycogen**:
- Glycogen is a homopolysaccharide composed solely of glucose units. It is primarily used as a storage form of energy in animals. Glycogen is formed by alpha-1,4 and alpha-1,6 glycosidic linkages, which allow for branching. Therefore, glycogen is classified as a storage polysaccharide.

3. **Analyzing Starch**:
- Starch is also a homopolysaccharide made up of glucose subunits. It consists of two components: amylose (which has alpha-1,4 linkages) and amylopectin (which has both alpha-1,4 and alpha-1,6 linkages). Starch serves as a carbohydrate reserve in plants, making it another storage polysaccharide.

4. **Analyzing Inulin**:
- Inulin is a heteropolysaccharide composed of both glucose and fructose units, linked by beta-1,2 glycosidic bonds. It acts as a storage carbohydrate in some plants, particularly in roots and rhizomes. Thus, inulin is also categorized as a storage polysaccharide.

5. **Analyzing Cellulose**:
- Cellulose is a homopolysaccharide made up of glucose units linked by beta-1,4 glycosidic bonds. It is a crucial component of the plant cell wall, providing structural support. Therefore, cellulose is classified as a structural polysaccharide.

6. **Conclusion**:
- Among the options provided, cellulose is the only structural polysaccharide. Glycogen, starch, and inulin are all storage polysaccharides.

### Final Answer:
**Cellulose is the structural polysaccharide.**

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