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Ultraviolet

Ultraviolet

(Science: physics) continuous spectrum beyond the violet end of the visible spectrum (wavelength less than 400nm) and above the x-ray wavelengths (greater than 5 nm).

glass absorbs uv, so optical systems at these wavelengths have to be of quartz. Nucleic acids absorb uv most strongly at around 260nm and this is the wavelength most likely to cause mutational damage (by the formation of thymine dimers).

It is the uv component of sunlight that causes actinic keratoses to form in skin, but that is also required for vitamin d synthesis.


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Skin Cancer/DNA damage/ Cell division Question?

- Scientists believe that some cancers are hereditary. One form of cancer is caused by ultraviolet radiation such as the type produced by the sun. It causes damage to the DNA that controls cell division. Disabling the control mechanisms for mitosis can result in various ...

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by rosarioduniam89
Sun Jan 11, 2009 11:45 pm
 
Forum: Molecular Biology
Topic: Skin Cancer/DNA damage/ Cell division Question?
Replies: 1
Views: 613

main features of the current theory of the origin of life

so way back in the day... when life on earth wasn't quite formed yet... the atmosphere was subjected to bursts of energy from ultraviolet rays, eletrical discharge in the form of lightning, heat from volcanic eruptions, hot springs and radioactive decay... from all of this, organic molecules ...

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by rajvandam
Sun Sep 14, 2008 11:57 pm
 
Forum: General Discussion
Topic: main features of the current theory of the origin of life
Replies: 0
Views: 421

Tans

... is one kind of adaptation. South East Asia locates around the equator which receiving sunlight almost everytime. Tanning functions to filter ultraviolet and other harmful lights not to be absorbed by skin. That's why your skin turns into darker because originally you come from country which ...

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by Dr.Stein
Mon Jul 23, 2007 2:08 am
 
Forum: Human Biology
Topic: Tans
Replies: 7
Views: 1329

why is green photosynthesis so dominant?

... hypothesis was true, then nothing would have black pigments - or pigments that absorb particularly energetic frequencies, such as the purples or ultraviolet. As it is, chlorophyll absorbs a pretty wide range of frequencies, at a heavy peak of intensity.

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by Darby
Thu May 17, 2007 7:47 pm
 
Forum: Evolution
Topic: why is green photosynthesis so dominant?
Replies: 14
Views: 2737

help+ not sure?!

what is the role of ACTH when the skin is exposed to ultraviolet light? :?

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by frogsrcool
Wed Mar 14, 2007 9:04 pm
 
Forum: General Discussion
Topic: help+ not sure?!
Replies: 4
Views: 784
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