Glycosidic linkage at place of branching in starch and glycogen is

Options

A. `alpha- 1-4`
B. `beta, 1-4`
C. `beta, 1-6`
D. `alpha, 1-6`

Answer

To solve the question regarding the glycosidic linkage at the place of branching in starch and glycogen, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Glycosidic Linkages**: Glycosidic linkages are covalent bonds formed between carbohydrates when they connect with other functional groups. In the context of polysaccharides like starch and glycogen, these linkages are crucial for their structure.

2. **Identifying Starch and Glycogen**: Both starch and glycogen are homopolysaccharides made up of glucose units. They have different structural forms: starch can be linear (amylose) or branched (amylopectin), while glycogen is highly branched.

3. **Analyzing the Linkages**:
- In the linear form of starch and glycogen, the glucose units are connected by **alpha 1,4 glycosidic linkages**.
- However, when we talk about branching in these polysaccharides, we need to identify the type of glycosidic linkage that occurs at the branching points.

4. **Branching Linkages**: The branching in both starch (specifically amylopectin) and glycogen occurs through **alpha 1,6 glycosidic linkages**. This means that at the points where the chains branch off, the glucose units are connected by an alpha 1,6 bond.

5. **Final Answer**: Therefore, the glycosidic linkage at the place of branching in starch and glycogen is **alpha 1,6**. Thus, the correct option is **D**.