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# Secondary Magazine - Issue 29: Focus on

This page has been archived. The content was correct at the time of original publication, but is no longer updated.
Created on 03 March 2009 by ncetm_administrator
Updated on 27 April 2009 by ncetm_administrator

# Focus on...the helix

Wikipedia states that:

A helix (pl: helixes or helices) is a special kind of space curve, i.e. a smooth curve in three-space. As a mental image of a helix, one may take the spring (although the spring is not a curve, and so is technically not a helix, it does give a convenient mental picture). A helix is characterised by the fact that the tangent line at any point makes a constant angle with a fixed line. A filled in helix, for example a spiral staircase, is called a helicoid. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word helix comes from the Greek word έλιξ.

In mathematics, a helix is a curve in 3-dimensional space.

The following parametrisation in Cartesian coordinates defines a helix:

x(t) = cos (t)
y(t) = sin (t)
z(t) = t

As the parameter t increases, the point (x(t),y(t),z(t)) traces a right-handed helix of pitch 2π about the z-axis, in a right-handed coordinate system.

From Wikipedia

Hedera helix
is the Latin name for ivy.

The sentence, "This structure has novel features which are of considerable biological interest" may be one of science's most famous understatements.

It appeared in April 1953 in the scientific paper where James Watson and Francis Crick presented the structure of the DNA-helix, the molecule that carries genetic information from one generation to the other.

Nine years later, in 1962, they shared the Nobel Prize in Physiology or Medicine with Maurice Wilkins, for solving one of the most important of all biological riddles. Half a century later, important new implications of this contribution to science are still coming to light.

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