^ m d. In the document, Nursing: Scope and Standards of Practice, scope of practice is defined by the âwho,â âwhat,â âwhere,â âwhen,â âwhy,â and âhowâ of nursing practice, including advanced practice nursing. In addition, there are other documents relevant to specialties.
double helix. double helix. double helix. The coiled structure of double-stranded DNA in which strands linked by hydrogen bonds form a spiral configuration, with the two strands oriented in opposite directions.
The term entered popular culture with the publication in 1968 of The Double Helix: A Personal Account of the Discovery of the Structure of DNA, by James Watson. The DNA double helix polymer of nucleic acid, held together by nucleotides which base pair together. In B-DNA, the most common double helical structure found in nature, the double helix is right-handed with about 10â10.5 base pairs per turn. The double helix structure of DNA contains a major groove and minor groove. In B-DNA the major groove is wider than the minor groove. Given the difference in widths of the major groove and minor groove, many proteins which bind to B-DNA do so through the wider major groove.