Which of the given statements is INCORRECT about glycogen ?

Options

A. It is a straight chain polymer similar to amylose
B. It is present in animal cells
C. It is present in some yeast and fungi
D. Only `alpha-`linkages are present in the molecule

Explanation

To determine which statement about glycogen is incorrect, we need to analyze the properties and characteristics of glycogen based on the information provided.

### Step-by-Step Solution:

1. **Understanding Glycogen**: Glycogen is a polysaccharide that serves as a form of energy storage in animals and some fungi and yeast. It is primarily composed of glucose units.

2. **Structure of Glycogen**: Glycogen is a branched polymer of glucose. It consists of chains of glucose molecules linked together primarily by α(1→4) glycosidic bonds, with branches formed by α(1→6) glycosidic bonds approximately every 8 to 12 glucose units.

3. **Comparison with Amylose**: Amylose is a linear polysaccharide made up of glucose units connected by α(1→4) glycosidic bonds. In contrast, glycogen is branched, which distinguishes it from amylose.

4. **Function of Glycogen**: Glycogen acts as an energy reservoir. When the body requires energy, glycogen can be broken down into glucose molecules through a process called glycogenolysis, primarily catalyzed by the enzyme glycogen phosphorylase.

5. **Storage of Glycogen**: In humans, excess glucose is converted into glycogen and stored mainly in the liver and muscle cells. This stored glycogen can be mobilized when energy is needed.

6. **Identifying the Incorrect Statement**: The question asks for the incorrect statement about glycogen. The transcript indicates that the first statement incorrectly describes glycogen as a straight-chain polymer similar to amylose, which is not true since glycogen is branched.

### Conclusion:
The incorrect statement about glycogen is that it is a straight-chain polymer similar to amylose. Therefore, the answer is **Option 1**.