To determine the partner nitrogen base sequence of T-C-A-G-C-A, we need to use the base-pairing rules of DNA, which state:
- Thymine (T) pairs with Adenine (A)
- Cytosine (C) pairs with Guanine (G)
- Adenine (A) pairs with Thymine (T)
- Guanine (G) pairs with Cytosine (C)
Let's find the partner sequence step-by-step.
1. The first base in the given sequence is T. According to the base-pairing rules, T pairs with A.
2. The second base is C. According to the base-pairing rules, C pairs with G.
3. The third base is A. According to the base-pairing rules, A pairs with T.
4. The fourth base is G. According to the base-pairing rules, G pairs with C.
5. The fifth base is C. According to the base-pairing rules, C pairs with G.
6. The sixth base is A. According to the base-pairing rules, A pairs with T.
Putting these together, the partner sequence corresponding to T-C-A-G-C-A is A-G-T-C-G-T.
Now, let's match this partner sequence with the given choices:
- A-C-G-A-C-T
- C-A-G-A-T-G
- A-G-T-C-G-T
- T-C-A-G-C-A
The partner sequence A-G-T-C-G-T exactly matches the third choice.
Therefore, the correct answer is:
A-G-T-C-G-T
