In the base sequence of one strand of DNA is `GAT, TAG, CAT, GAC` what shall be the sequence of its complementary strand -

Options

A. CAT,CTG,ATC,GTA
B. GTA,ATC,CTG,GTA
C. ATC,GTA,CTG,GTA
D. CTA,ATC,GTA,CTG

Answer

To find the complementary strand of the given DNA sequence `GAT, TAG, CAT, GAC`, we need to follow these steps:

### Step 1: Identify the Base Pairing Rules
In DNA, the bases pair according to specific rules:
- Adenine (A) pairs with Thymine (T)
- Thymine (T) pairs with Adenine (A)
- Cytosine (C) pairs with Guanine (G)
- Guanine (G) pairs with Cytosine (C)

### Step 2: Write Down the Given Sequence
The given sequence of one strand of DNA is:
- GAT
- TAG
- CAT
- GAC

### Step 3: Find the Complementary Bases
Now, we will find the complementary base for each base in the given sequence:
1. G (Guanine) pairs with C (Cytosine)
2. A (Adenine) pairs with T (Thymine)
3. T (Thymine) pairs with A (Adenine)

Continuing this for the entire sequence:
- For GAT:
- G → C
- A → T
- T → A
- So, GAT → CTA

- For TAG:
- T → A
- A → T
- G → C
- So, TAG → ATC

- For CAT:
- C → G
- A → T
- T → A
- So, CAT → GTA

- For GAC:
- G → C
- A → T
- C → G
- So, GAC → CTA

### Step 4: Combine the Complementary Bases
Now we combine all the complementary sequences:
- GAT → CTA
- TAG → ATC
- CAT → GTA
- GAC → CTA

So, the full complementary strand is:
- CTA ATC GTA CTA

### Final Answer
The sequence of the complementary strand is:
**CTA ATC GTA CTA**