When a phosphate group is linked to _____ a nucleoside through ______ a corresponding nucleotide or deoxynucleotide is formed

Options

A. 3'-OH, phosphoester linkage
B. 2'-OH, glycosidic linkage
C. 5'-OH, phosphoester linkage
D. 1'-OH, phosphoester linkage

Answer

To answer the question, we need to identify the missing components in the statement regarding the formation of a nucleotide or deoxynucleotide from a nucleoside.

### Step-by-Step Solution:

1. **Understanding Nucleosides and Nucleotides**:
- A nucleoside consists of a nitrogenous base and a sugar (either ribose or deoxyribose) but does not contain a phosphate group.
- A nucleotide, on the other hand, is formed when a phosphate group is added to a nucleoside.

2. **Identifying the Components**:
- The question asks for the specific part of the nucleoside that the phosphate group is linked to. In nucleosides, the sugar has different carbon atoms, and the phosphate group is typically linked to the 5' carbon of the sugar.

3. **Linkage Type**:
- The type of bond formed when a phosphate group is attached to the sugar is known as a phosphoester bond. This bond forms when the hydroxyl (OH) group on the 5' carbon of the sugar reacts with the phosphate group.

4. **Finalizing the Answer**:
- Therefore, the complete statement should read: "When a phosphate group is linked to **5'OH** of a nucleoside through **phosphoester linkage**, a corresponding nucleotide or deoxynucleotide is formed."

### Final Answer:
When a phosphate group is linked to **5'OH** of a nucleoside through **phosphoester linkage**, a corresponding nucleotide or deoxynucleotide is formed.

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