What describes the arrangement of DNA strands that run in opposite directions?

Antiparallel DNA accurately describes the arrangement of the two strands of a DNA molecule that run in opposite directions. In a DNA double helix, one strand runs in the 5' to 3' direction, while the other strand runs in the 3' to 5' direction. This orientation is crucial for the processes of DNA replication and transcription, as enzymes that interact with DNA can only add nucleotides in the 5' to 3' direction.

This antiparallel arrangement allows for the formation of hydrogen bonds between complementary base pairs (adenine with thymine and guanine with cytosine), ensuring the stability and fidelity of the DNA structure. Understanding this arrangement is fundamental to molecular biology and genetics, as it impacts how genetic information is copied and expressed within biological systems.