The molety present at the 5' end of ribose sugar in a polynucleotide is

Options

A. OH
B. `CH_(2)`
C. phosphate
D. adenine

Answer

To determine the moiety present at the 5' end of ribose sugar in a polynucleotide, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of a Nucleotide**:
- A nucleotide consists of three components: a pentose sugar (ribose or deoxyribose), a nitrogenous base (such as adenine, guanine, cytosine, or thymine/uracil), and a phosphate group.

2. **Identify the Pentose Sugar**:
- In this case, we are focusing on ribose sugar, which has five carbon atoms. The structure of ribose includes five carbons labeled as C1, C2, C3, C4, and C5.

3. **Locate the 5' End**:
- The 5' end of the ribose sugar refers to the carbon atom that is numbered as C5. In ribose, the C5 carbon is attached to a phosphate group in a nucleotide.

4. **Determine the Moiety at the 5' End**:
- At the 5' end of ribose sugar in a polynucleotide, the moiety present is an inorganic phosphate group (PO4). This phosphate group is attached to the C5 carbon of the ribose sugar.

5. **Conclusion**:
- Therefore, the moiety present at the 5' end of ribose sugar in a polynucleotide is an inorganic phosphate group.

### Summary Answer:
The moiety present at the 5' end of ribose sugar in a polynucleotide is an inorganic phosphate group (PO4).

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