| HD | Haab-Dimmer [syndrome]; Hajna-Damon [broth]; Hansen disease; hearing distance; heart disease; helix ... |
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| HPA | Health Care Practice Act; Health Policy Agenda for the American People; health promotion advocates; ... |
| HPH | Helix pomatia hemocyanin |
| crus of helix | A transverse ridge continuing backward from the helix of the auricle, dividing the concha into an upper portion (cymba) and a lower portion (cavity of concha). Synonym: crus helicis, crista helicis, limb of helix. (05 Mar 2000) |
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| helix | <chemistry, molecular biology> A spiral structure in a macromolecule that contains a repeating pattern. (09 Oct 1997) |
| helix-coil transition | <molecular biology> A change in the structure of a nucleic acid or protein molecule from a highly ordered, complex structure to a random, chaotic structure. Also means that the protein or nucleic acid becomes denatured. (09 Oct 1997) |
| helix destabilising protein | <molecular biology, protein> Proteins involved in DNA replication. They bind cooperatively to single stranded areas of a DNA molecule in a double helix, causing the helix to unwind and preventing the reformation of the duplex and extending the DNA backbone, thus making the exposed bases more accessible for base pairing. (10 Oct 1997) |
| helix (snails) | A genus of chiefly eurasian and african land snails including the principal edible snails as well as several pests of cultivated plants. (12 Dec 1998) |
| smaller muscle of helix | <anatomy> A band of oblique fibres covering the crus of the helix of the auricle. Synonym: musculus helicis minor, smaller muscle of helix. (05 Mar 2000) |
| spine of helix | An anteriorly directed spine at the extremity of the crus of the helix of the auricle. Synonym: spina helicis, apophysis helicis. (05 Mar 2000) |
| DNA helix | The helical structure assumed by two strands of deoxyribonucleic acid, held together throughout their length by hydrogen bonds between bases on opposite strands, referred to as Watson-Crick base pairing. See: base pair. Synonym: DNA helix, double helix, twin helix. (05 Mar 2000) |
| double helix | <molecular biology> Conformation or shape that two linear strands of DNA assume when bonded together and become twisted into a helix. (10 Nov 1998) |
| tail of helix | A flattened process terminating the cartilage of the helix of the ear, posteriorly and inferiorly. Synonym: cauda helicis. (05 Mar 2000) |
| triple helix | The superhelix formed (right-handed) from three individual collagen helices (each being left-handed). (05 Mar 2000) |
| twin helix | The helical structure assumed by two strands of deoxyribonucleic acid, held together throughout their length by hydrogen bonds between bases on opposite strands, referred to as Watson-Crick base pairing. See: base pair. Synonym: DNA helix, double helix, twin helix. (05 Mar 2000) |
| 3.613 helix | The helical (commonly right-handed) form present in many proteins, deduced by Pauling and Corey from X-ray diffraction studies of proteins such as alpha-keratin; the helix is stabilised by hydrogen bonds between, e.g., ==C==O and HN== groups (symbolised by the centre dot in ==CO-HN==) of different eupeptide bonds. In a true a helix, there are 3.6 amino acid residues per turn of the helix. Synonym: 3.613 helix, Pauling-Corey helix. Collagen helix, an extended left-handed helix resulting from the high levels of glycine, l-proline, and l-hydroxyproline present in the collagens. There are 3.3 amino acids per turn of the helix. Three of those left-handed helices form a triple superhelix that is right-handed. (05 Mar 2000) |
| large muscle of helix | <anatomy> A narrow band of muscular fibres on the anterior border of the helix of the auricle arising from the spine and inserted at the point where the helix becomes transverse. Synonym: musculus helicis major, large muscle of helix. (05 Mar 2000) |
| fossa of helix | 1. The longitudinal furrow between the helix and the antihelix of the auricle. Synonym: fossa of helix, scaphoid fossa. 2. Obsolete term for scaphoid fossa. Origin: L. Fr. G. Skaphe, skiff (05 Mar 2000) |