In the double helix of DNA , the two strands are oriented chemically in opposite directions , which permits base pairing by providing complementarity between the two bases .
Which is essential for replication of or transcription of the encoded information found in DNA .
In the double helix of DNA , the two strands are oriented chemically in opposite directions , which permits base pairing by providing complementarity between the two bases , and which is essential for replication of or transcription of the encoded information found in DNA .