Final Answer:
In the context of DNA structure, each strand runs antiparallel to the other. This means that one strand runs in the 5' to 3' direction, while the complementary strand runs in the opposite 3' to 5' direction.
Step-by-step explanation:
The antiparallel orientation of DNA strands is a fundamental feature of the DNA double helix structure. It refers to the opposite directionality of the two polynucleotide strands that make up the helix. In the 5' to 3' direction, the DNA strand has a free phosphate group at the 5' end and a free hydroxyl group at the 3' end.
The complementary strand, on the other hand, runs in the opposite direction, with a free hydroxyl group at the 5' end and a free phosphate group at the 3' end.
This antiparallel arrangement is essential for the formation of hydrogen bonds between complementary base pairs (adenine with thymine, and guanine with cytosine) in the center of the helix. The hydrogen bonding occurs in a specific manner: adenine pairs with thymine, forming two hydrogen bonds, while guanine pairs with cytosine, forming three hydrogen bonds. This base pairing, facilitated by the antiparallel orientation, ensures the stability and specificity of the DNA double helix.
Understanding the antiparallel nature of DNA strands is crucial in molecular biology, genetics, and the study of DNA replication and transcription. It provides the basis for the accurate and faithful transmission of genetic information during cellular processes.