In AGST of DNA hydrogen bonds and base pairigs occur between

Options

A. A - U,C -G
B. A - C,G - T
C. A -G, C -T
D. A - T, C - G

Answer

To answer the question regarding the hydrogen bonds and base pairing in DNA, we can break down the information as follows:

### Step-by-Step Solution:

1. **Understanding DNA Structure**: DNA is composed of nucleotides, which are the building blocks of DNA. Each nucleotide consists of a nitrogenous base, a sugar (deoxyribose), and a phosphate group.

2. **Identifying Nitrogenous Bases**: In DNA, there are two categories of nitrogenous bases:
- **Purines**: Adenine (A) and Guanine (G)
- **Pyrimidines**: Cytosine (C) and Thymine (T)

3. **Base Pairing Rules**: The nitrogenous bases pair specifically:
- Adenine (A) pairs with Thymine (T) through **two hydrogen bonds**.
- Guanine (G) pairs with Cytosine (C) through **three hydrogen bonds**.

4. **Conclusion**: Therefore, in the context of the question, hydrogen bonds and base pairings occur between:
- Adenine (A) and Thymine (T)
- Guanine (G) and Cytosine (C)

### Final Answer:
In DNA, hydrogen bonds and base pairings occur between Adenine (A) and Thymine (T), and between Guanine (G) and Cytosine (C).

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