Biological pigment



Main article: Pigment

 

In biology, a pigment or biochrome is any material resulting in color of plant or animal cells, which is the result of selective melanin) in specialized cells called chromatophores.

Pigment color differs from structural color in that it is the same for all viewing angles, whereas structural color is the result of selective reflection or iridescence, usually because of multilayer structures. For example, butterfly wings typically contain structural color, although many butterflies have cells that contain pigment as well.

Biological pigments

Pigments in plants

   

Among the most important molecules for plant function are the light while reflecting others. The light that is absorbed may be used by the plant to power chemical reactions, while the reflected wavelengths of light determine the color the pigment will appear to the eye. Pigments also serve to attract pollinators.

photosynthesis. chlorophyll is the reason most plants are of the colour green.

antioxidants and to promote healthy eyesight in humans.

leaves, stems, roots, flowers, and fruits, though not always in sufficient quantities to be noticeable. Anthocyanins are most visible in the petals of flowers, where they may make up as much as 30% of the dry weight of the tissue.[1] They are also responsible for the purple color seen on the underside of tropical shade plants such as Tradescantia zebrina; in these plants, the anthocyanin catches light that has passed through the leaf and reflects it back towards regions bearing chlorophyll, in order to maximize the use of available light.

beets, and are used commercially as food-coloring agents.

Pigments in animals

 

Pigments in animals may serve to protect tissues from melanin in the skin. Pigments may also aid in sexual reproduction, identifying species and gender of animals to potential mates, or signalling readiness to breed.

Some cephalopods use pigmented chromatophores to communicate.

Pigmentation is used by many animals for protection, by means of camoflauge, mimicry, or warning coloration. Camilions also use pigments to blend into surrounds because they can control the absorption level of the electromagnetic spectrum.

Diseases and conditions

A variety of diseases and abnormal conditions that involve pigmentation arise in humans and animals, either from absence of or loss of pigmentation or pigment cells, or from the excess production of pigment.

  • Albinism is an inherited disorder characterized by total or partial loss of melanin. Humans and animals that suffer from albinism are called "albinistic" (the term "albino" is also sometimes used, but may be considered offensive when applied to people).
  • Lamellar ichthyosis, also called "fish scale disease", is an inherited condition in which one symptom is excess production of melanin. The skin is darker than normal, and is characterized by darkened, scaly, dry patches.
  • Melasma is a condition in which dark brown patches of pigment appear on the face, influenced by hormonal changes. When it occurs during a pregnancy, this condition is called the mask of pregnancy.
  • ocular pigmentation is an accumulation of pigment in the eye, and may be caused by latanoprost medication.[2]
  • Vitiligo is a condition in which there is a loss of pigment-producing cells called melanocytes in patches of skin.

Commercial uses

Pigments may be extracted and used as dyes.

References

  1. ^ Robinson, Trevor. 1963. The Organic Constituents of Higher Plants, page 183 (Minneapolis: Burgess Publishing).
  2. ^ Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. ISBN 0-443-07145-4.  Page 146
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Types of Plant Pigments
chlorophyll
 
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