List a difference between nucleoside and nucleotide.

Explanation

### Step-by-Step Solution

1. **Definition of Nucleoside**: A nucleoside is a molecular structure that consists of a nitrogenous base (such as adenine, guanine, cytosine, or uracil) attached to a pentose sugar (either ribose or deoxyribose). Importantly, a nucleoside does not contain a phosphate group.

2. **Definition of Nucleotide**: A nucleotide is a more complex structure that includes a nitrogenous base, a pentose sugar, and one or more phosphate groups. The presence of the phosphate group is what differentiates a nucleotide from a nucleoside.

3. **Comparison**:
- **Nucleoside**: Composed of a nitrogenous base + pentose sugar (no phosphate group).
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