Unlike plant cell walls, which are made of cellulose, most bacterial cell walls contain ................

Explanation

**Step-by-Step Solution:**

1. **Identify the Composition of Plant Cell Walls:**
- Plant cell walls are primarily composed of cellulose, a complex carbohydrate that provides structural support.

2. **Understand the Composition of Bacterial Cell Walls:**
- Unlike plant cells, bacterial cell walls do not contain cellulose. Instead, they are primarily made up of a substance called peptidoglycan.

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