Which one is correct base pairing for DNA molecules ?

Options

A. Cytosine`" " -" "`Uracil
B. Thymine `" " -" "`Guanine
C. Thiamine `" " -" "`Adenine
D. Cytosine`" " -" "`Guanine

Answer

To determine the correct base pairing for DNA molecules, we need to understand the specific pairs of nitrogenous bases that form the structure of DNA. Here’s a step-by-step solution:

### Step 1: Identify the Nitrogenous Bases
DNA consists of four nitrogenous bases:
- Adenine (A)
- Thymine (T)
- Cytosine (C)
- Guanine (G)

### Step 2: Understand Base Pairing Rules
In DNA, the base pairing follows specific rules:
- Adenine (A) pairs with Thymine (T) through two hydrogen bonds.
- Guanine (G) pairs with Cytosine (C) through three hydrogen bonds.

### Step 3: Evaluate the Given Options
Now, let's evaluate the possible pairings:
1. **Adenine (A) with Thymine (T)** - Correct pairing.
2. **Guanine (G) with Cytosine (C)** - Correct pairing.
3. **Cytosine (C) with Uracil (U)** - Incorrect, as Uracil is found in RNA, not DNA.
4. **Thymine (T) with Guanine (G)** - Incorrect, as Thymine pairs with Adenine.

### Step 4: Identify the Correct Pairing
From the evaluation, the correct base pairing in DNA is:
- **Cytosine (C) pairs with Guanine (G)**.

### Conclusion
The correct answer to the question "Which one is correct base pairing for DNA molecules?" is:
**Cytosine (C) pairs with Guanine (G)**.

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