One strand of a fragment of duplex DNA has the sequence 5'-ATCGACCTGATC-3'.
What is the sequence of the other strand in the duplex?

Verified step by step guidance

1. Identify the sequence of the given DNA strand: 5'-ATCGACCTGATC-3'.
2. Recall the base-pairing rules in DNA: Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G).
3. Write the complementary sequence by pairing each base with its complement: A pairs with T, T pairs with A, C pairs with G, and G pairs with C.
4. Reverse the direction of the complementary strand to ensure it is written in the 5' to 3' direction, as DNA strands are antiparallel.
5. The final complementary sequence will be the reverse complement of the original strand, written in the 5' to 3' orientation.

Key Concepts

Complementary Base Pairing

In DNA, the two strands are held together by complementary base pairing, where adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). This means that for every A in one strand, there is a T in the opposite strand, and for every C, there is a G. Understanding this pairing is essential for determining the sequence of the complementary strand.

DNA Strand Orientation

DNA strands have directionality, indicated by the 5' and 3' ends. The 5' end has a phosphate group, while the 3' end has a hydroxyl group. When writing DNA sequences, the convention is to list them from the 5' to 3' direction, which is crucial for accurately determining the complementary strand's sequence.

Antiparallel Structure of DNA

The two strands of DNA run in opposite directions, a feature known as antiparallel orientation. This means that if one strand runs from 5' to 3', the complementary strand runs from 3' to 5'. This structural characteristic is important for understanding how the strands interact and how replication and transcription processes occur.