A unit consisting of a base bonded to a sugar is referred to as:

Options

A. Nucleoside
B. Glycosicde
C. Purine
D. Nucleotide

Answer

To answer the question "A unit consisting of a base bonded to a sugar is referred to as:", we can follow these steps:

### Step-by-Step Solution

1. **Understanding the Components**:
- The question refers to a unit that consists of two components: a base and a sugar.

2. **Identifying the Type of Sugar**:
- The sugar in question is typically a pentose sugar, which can be either ribose (found in RNA) or deoxyribose (found in DNA).

3. **Identifying the Type of Base**:
- The base is a nitrogenous base, which can be classified into two categories: purines (like adenine and guanine) and pyrimidines (like cytosine, thymine, and uracil).

4. **Combining the Components**:
- When a nitrogenous base is bonded to a sugar, it forms a specific type of molecule.

5. **Defining the Correct Term**:
- The combination of a nitrogenous base and a sugar is specifically referred to as a **nucleoside**.

6. **Distinguishing from Related Terms**:
- It is important to differentiate this from a nucleotide, which includes a phosphate group in addition to the sugar and base.

### Final Answer
A unit consisting of a base bonded to a sugar is referred to as a **nucleoside**.

---