Cellulose in plant cell wall is made up of

Options

A. unbranched chain of glucose molecules linked by `alpha` ` 1 to 6` glycosidic bond
B. unbranched chain of glucose molecules linked by `beta , 1 to 4` glycosidic molecule
C. branched chain of glucose molecules linked by ` alpha, to 6 ` glycosidic bond in straight chain & ` beta to 1, 4 ` at the site of branching.
D. branched chains have ` alpha to 1, 4 ` bond and ` beta to 1, 6 ` glycosidic bonds both

Answer

### Step-by-Step Solution:

1. **Understanding Cellulose**: Cellulose is a crucial component of the plant cell wall. It provides structural support and helps maintain the shape of the plant cells.

2. **Composition of Plant Cell Wall**: The plant cell wall is primarily composed of cellulose, hemicellulose, pectin, and structural proteins. Specifically, cellulose constitutes about 30% of the cell wall.

3. **Nature of Cellulose**: Cellulose is classified as a polysaccharide, which means it is a carbohydrate made up of long chains of sugar molecules.

4. **Building Blocks of Cellulose**: The basic building blocks of cellulose are unbranched chains of beta-D-glucose units. These glucose units are linked together by specific types of bonds.

5. **Linkage in Cellulose**: The glucose units in cellulose are connected by beta 1,4-glycosidic bonds. This means that the first carbon of one glucose molecule is linked to the fourth carbon of the next glucose molecule in the chain.

6. **Synthesis of Cellulose**: The synthesis of cellulose occurs at the plasma membrane of plant cells, facilitated by an enzyme complex known as cellulose synthase.

7. **Interactions Between Chains**: The cellulose chains are stabilized by hydrogen bonds and van der Waals forces, which help maintain the integrity and strength of the cell wall.

### Final Answer:
Cellulose in the plant cell wall is made up of unbranched beta 1,4-D-glucose units.