helix

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helix

 [he´liks] (pl. he´lices, helixes) (Gr.)
1. a winding structure; see also coil and spiral.
2. the superior and posterior free margin of the pinna of the ear.
α-helix (alpha helix) the complex structural arrangement of parts of protein molecules in which a single polypeptide chain forms a right-handed helix.
double helix (Watson-Crick helix) the structure of deoxyribonucleic acid (DNA), consisting of two coiled chains, each of which contains information completely specifying the other chain.

he·lix

, pl.

hel·i·ces

(hē'liks, hel'i-sēz), [TA] Do not confuse this word with spiral.
1. The margin of the auricle; a folded rim of cartilage forming the upper part of the anterior, the superior, and the greater part of the posterior edges of the auricle.
2. A line in the shape of a coil (or a spring, or the threads on a bolt), each point being equidistant from a straight line that is the axis of the cylinder in which each point of the helix lies.
[L. fr. G. helix, a coil]

helix

(hē′lĭks)
n. pl. he·lixes or helices (hĕl′ĭ-sēz′, hē′lĭ-)
1. Mathematics A three-dimensional curve that lies on a cylinder or cone, so that its angle to a plane perpendicular to the axis is constant.
2. A spiral form or structure.
3. Anatomy The folded rim of skin and cartilage around most of the outer ear.
4. Architecture A volute on a Corinthian or Ionic capital.
v. he·lixed, he·lixing, he·lixes
v.tr.
To move or position (something) into the shape of a helix.
v.intr.
1. To have the shape of a helix.
2. To move along a helical course; spiral.
Anatomy The superior and posterior free margin of the pinna of the ear
Molecular biology A winding structural motif for nucleic acids and proteins

he·lix

, pl. helixes, pl. helices (hē'liks, -ĕz, hel'i-sēz)
1. [TA] The margin of the auricle; a folded rim of cartilage forming the upper part of the anterior, the superior, and the greater part of the posterior edges of the auricle.
2. A line in the shape of a coil (or a spring, or the threads on a bolt), each point being equidistant from a straight line that is the axis of the cylinder in which each point of the helix lies. usage note: Often mistakenly applied to a spiral.
[L. fr. G. helix, a coil]

helix

The folded margin of the outer ear. The form of the helix is determined by the underlying cartilage.

helix

(pl. helixes or helices) a form of spiral in which any point is at the same distance from the central axis. RNA molecules have a single helix, DNA is a double helix.