Final answer:
A nucleic acid sequence is indeed written in the 5' to 3' direction, following the orientation of synthesis and reading in biological systems. The sequences are antiparallel and complementary, with bases pairing according to Watson-Crick rules (A pairs with T and C pairs with G).
Step-by-step explanation:
Yes, unless specified otherwise, a nucleic acid sequence is always written in the 5' to 3' direction. This convention reflects the direction in which nucleic acid chains are synthesized and read in biological systems. In the context of DNA, which is double-stranded, one strand runs in the 5' to 3' direction (top strand) and is complementary to the other strand, which runs in the opposite 3' to 5' direction (bottom strand). As such, the sequence of nucleotides carries the genetic information in its primary structure.c For example, if the sequence of the 5'-3' strand is GGCTACATTCGGAA, then the sequence for the other DNA strand would be CCGATGTAAGCCTT because the DNA strands are antiparallel and complementary, adhering to Watson-Crick base pairing.
Absolutely, the convention of writing nucleic acid sequences from 5' to 3' holds true in molecular biology. This convention reflects the direction in which nucleic acid chains are synthesized and read in biological systems. In the context of DNA, the double-stranded structure consists of one strand running in the 5' to 3' direction (the top strand) and its complementary strand running in the opposite 3' to 5' direction (the bottom strand). This antiparallel arrangement is vital for Watson-Crick base pairing, ensuring proper complementary base interactions. For instance, if the sequence of the 5'-3' top strand is GGCTACATTCGGAA, the sequence of the complementary 3'-5' bottom strand would be CCGATGTAAGCCTT. This adherence to the 5' to 3' directionality is fundamental for accurately representing genetic information in nucleic acid sequences.