Select DNA sequence which would act as a restriction site

Options

A. `(A A C C G G)/(T T G G C C )`
B. `(G G T T G G)/(C C A A C C)`
C. `(A A G G C T)/(T T C C G A)`
D. `(C T G C A G)/(G A C G T C)`

Answer

To solve the question of selecting a DNA sequence that acts as a restriction site, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Restriction Sites**:
- Restriction sites are specific sequences of DNA that are recognized and cut by restriction enzymes (restriction endonucleases). These sequences are typically 4 to 8 base pairs long.

2. **Identify Characteristics of Restriction Sites**:
- Most restriction sites are palindromic, meaning that the sequence reads the same in the 5' to 3' direction on one strand as it does in the 5' to 3' direction on the complementary strand.

3. **Evaluate the Given Options**:
- We need to analyze each provided DNA sequence to determine if it is palindromic and fits the criteria for a restriction site.

4. **Analyze Each Option**:
- **Option 1: AACC GG**
- Complementary strand: TTGGCC
- Not palindromic (base pairs do not match).
- **Option 2: GGT TGG**
- Complementary strand: CCA ACC
- Not palindromic (base pairs do not match).
- **Option 3: AAGGCT**
- Complementary strand: TTC GAA
- Not palindromic (base pairs do not match).
- **Option 4: CTGCAG**
- Complementary strand: GAC TGC
- Palindromic (reads the same in both directions).

5. **Select the Correct Answer**:
- Based on the analysis, the only sequence that acts as a restriction site is **Option 4: CTGCAG**.

### Final Answer:
The DNA sequence that acts as a restriction site is **CTGCAG**.

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