Which one is polymer?

Options

A. Sucrose
B. Glycogen
C. Fructose
D. Lactose

Answer

To determine which of the given options is a polymer, we need to analyze each option based on its structure and classification.

### Step-by-Step Solution:

1. **Understanding Polymers**:
- A polymer is a large molecule composed of repeating structural units (monomers) connected by covalent chemical bonds. Polymers can be natural (like proteins and polysaccharides) or synthetic.

2. **Analyzing the Options**:
- **Option A: Sucrose**:
- Sucrose is a disaccharide, which means it is made up of two monosaccharide units (glucose and fructose). Since it consists of only two units, it is not a polymer.
- **Conclusion**: Incorrect option.

- **Option B: Glycogen**:
- Glycogen is a polysaccharide, which is a type of polymer. It is composed of many glucose units (ranging from hundreds to thousands) linked together by glycosidic bonds. Specifically, it has alpha 1,4 glycosidic linkages in its linear chains and alpha 1,6 linkages at its branching points.
- **Conclusion**: Correct option.

- **Option C: Fructose**:
- Fructose is a monosaccharide, which means it is a single sugar unit. It does not consist of repeating units and therefore cannot be classified as a polymer.
- **Conclusion**: Incorrect option.

- **Option D: Lactose**:
- Lactose is also a disaccharide, made up of two monosaccharides (glucose and galactose). Like sucrose, it does not qualify as a polymer due to its composition of only two units.
- **Conclusion**: Incorrect option.

3. **Final Answer**:
- The only option that qualifies as a polymer is **Glycogen** (Option B).