Exonulceases remove

Options

A. Nitrogen bases from the ends of DNA
B. Phosphates from the ends of DNA
C. Nucleosides from the ends of DNA
D. Nucleotides from the ends of DNA

Answer

### Step-by-Step Solution:

1. **Understanding Exonucleases**:
- Exonucleases are enzymes that play a crucial role in nucleic acid metabolism. They are proteins that remove nucleotides from the ends of DNA or RNA molecules.

2. **Function of Exonucleases**:
- The primary function of exonucleases is to cleave nucleotides one at a time from the ends of a nucleic acid chain. This process is essential for various cellular functions, including DNA repair, replication, and degradation.

3. **Analyzing the Options**:
- Option A: "nitrogen pieces from the ends of DNA" - This is incorrect as nitrogen bases are not removed by exonucleases.
- Option B: "phosphates from the ends of DNA" - This is also incorrect; while phosphates are part of the nucleotide structure, exonucleases do not specifically remove phosphates.
- Option C: "nucleosides from the ends of DNA" - This is incorrect; nucleosides are not the target of exonucleases.
- Option D: "nucleotides from the ends of DNA" - This is the correct option, as exonucleases specifically remove nucleotides from the ends of DNA or RNA.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Option D: nucleotides from the ends of DNA**.