Question

Complete the DNA sequence below such that the final sequence is identical to that of the complementary strand. Your answer would be a seven-letter string composed of letters A, C, T, and G only, e.g. TTCTCAG.

5′-CTTTAGATCTAAAG-3

Answer 1

To find the complementary DNA sequence to the given strand 5'-CTTTAGATCTAAAG-3', apply the base pairing rules of A with T and C with G. The answer is 5'-CTTTAGA-3', which matches the first seven nucleotides of the original strand's complementary sequence.

Step-by-step explanation:

The student's question pertains to the concept of DNA complementary base pairing, where adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Using this principle, to complete the original DNA sequence 5'-CTTTAGATCTAAAG-3' with a sequence that is identical to the complementary strand, we take the base pair rules and write the complementary string in the 5' to 3' direction. Consequently, the completed sequence is 5'-CTTTAGA-3'.

To provide additional context with examples:

• If a DNA strand contains the sequence 5'-ATTCCGGATCGA-3', the complementary strand would be 5'-TAAGGCCTAGCT-3'.
• Given the sequence 5'-CCAGTGAATTGCCTAT-3', the complementary sequence is 3'-GGTCAGTTAACGGATA-5'.
• For the sequence 5'-TCCATGAGTTGA-3', the corresponding complementary sequence is 5'-ACTCACTGGAAT-3'.