Which of the following is not application of RNA `:`

Options

A. Complementary base pairing
B. 5' phosphoryl and 3' hybroxyl ends
C. Heterocyclic nitrogenous bases
D. Chargaff's rule

Answer

To determine which of the following is not an application of RNA, we need to analyze the functions and characteristics of RNA in comparison to DNA, particularly focusing on the context of the question.

### Step-by-Step Solution:

1. **Understanding RNA**:
- RNA stands for ribonucleic acid and is a crucial molecule in various biological processes. It is primarily involved in protein synthesis and can also serve as genetic material in some viruses.

2. **Identifying Characteristics of RNA**:
- RNA is typically single-stranded.
- It contains ribose sugar, unlike DNA which contains deoxyribose.
- The nitrogenous base thymine (T) found in DNA is replaced by uracil (U) in RNA.

3. **Complementary Base Pairing**:
- In RNA, base pairing occurs where adenine (A) pairs with uracil (U), and cytosine (C) pairs with guanine (G). This is important for processes like transcription and translation.

4. **Applications of RNA**:
- RNA plays various roles including:
- Messenger RNA (mRNA) carries genetic information from DNA to ribosomes for protein synthesis.
- Transfer RNA (tRNA) helps in the translation of mRNA into proteins.
- Ribosomal RNA (rRNA) is a component of ribosomes, facilitating protein synthesis.

5. **Chagaff's Rule**:
- Chagaff's rule states that in double-stranded DNA, the amount of adenine (A) is equal to thymine (T) and the amount of guanine (G) is equal to cytosine (C). This rule applies specifically to double-stranded DNA and does not apply to RNA.

6. **Conclusion**:
- Based on the analysis, the application that is not relevant to RNA is Chagaff's rule, as it pertains specifically to the base pairing in double-stranded DNA.

### Final Answer:
The application that is not related to RNA is **Chagaff's rule**.

---