DNA is a polymer of nucleotides which are linked to each other by `3'-5'` phosphodiester bond . To prevent polymerisation of nucleotides, which of the following modifications would you choose ?

Options

A. Replace purine with pyrimindines
B. Remove/ Replace 3' OH group in deoxy ribose
C. Remove/Replace2' OH group with some other group in deoxy ribose
D. Both (b) and (c)

Explanation

To solve the question regarding preventing the polymerization of nucleotides in DNA, we need to understand the structure of nucleotides and the role of specific functional groups in the polymerization process. Here’s a step-by-step solution:

### Step 1: Understand the Structure of Nucleotides
Nucleotides are the building blocks of DNA and consist of three components: a phosphate group, a sugar (deoxyribose in DNA), and a nitrogenous base (adenine, thymine, cytosine, or guanine). The nucleotides are linked together by phosphodiester bonds, specifically between the 3' hydroxyl (-OH) group of one nucleotide and the 5' phosphate group of another.

**Hint:** Recall the structure of nucleotides and the significance of the 3' and 5' ends in DNA polymerization.

### Step 2: Identify the Role of the 3' -OH Group
The 3' -OH group of the deoxyribose sugar is crucial for the formation of the phosphodiester bond. This -OH group allows the incoming nucleotide to attach and continue the polymerization process. If this group is modified or removed, the nucleotide cannot link to the growing DNA strand.

**Hint:** Focus on the functional groups that facilitate the bonding between nucleotides.

### Step 3: Analyze the Options Given
The options provided in the question include:
1. Replace purine with pyrimidine
2. Remove or replace the 3'-OH group in the deoxyribose
3. Remove or replace the 2'-OH group with some other group in deoxyribose
4. Both B and C

Among these options, removing or replacing the 3'-OH group would directly prevent the addition of new nucleotides, thereby halting polymerization.

**Hint:** Consider how each modification would affect the ability of nucleotides to bond.

### Step 4: Conclusion
Based on the analysis, the best modification to prevent the polymerization of nucleotides is to **remove or replace the 3'-OH group in the deoxyribose**. This modification would effectively stop the formation of phosphodiester bonds, thus preventing DNA polymerization.

**Final Answer:** The correct choice is **Option 2: Remove or replace the 3'-OH group in the deoxyribose.**