In the polynucleotide chain of DNA, a nitrogenous base is linked to the -OH of:

Options

A. 2'C pentose sugar
B. 3'C pentose sugar
C. 5'C penotse sugar
D. 1'C pentose sugar

Answer

To solve the question regarding where a nitrogenous base is linked in the polynucleotide chain of DNA, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Structure of DNA**:
- DNA is composed of a backbone made of deoxyribose sugar and phosphate groups, with nitrogenous bases attached to the sugar.

2. **Identifying the Components**:
- The nitrogenous bases in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T).
- The sugar in DNA is deoxyribose, which is a pentose sugar (5-carbon sugar).

3. **Examining the Pentose Sugar**:
- The structure of deoxyribose has five carbon atoms, labeled as 1', 2', 3', 4', and 5'.
- The 1' carbon is where the nitrogenous base attaches.
- The 5' carbon is involved in forming a phosphodiester bond with the phosphate group of the next nucleotide.

4. **Linkage of Nitrogenous Base**:
- The nitrogenous base is linked to the 1' carbon of the deoxyribose sugar through a glycosidic bond.
- This bond formation involves the loss of a water molecule (dehydration reaction).

5. **Conclusion**:
- Therefore, the nitrogenous base in the polynucleotide chain of DNA is linked to the -OH group of the 1' carbon of the deoxyribose sugar.

### Final Answer:
The nitrogenous base is linked to the -OH of the **1' carbon** of the deoxyribose sugar in the polynucleotide chain of DNA.

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