Dictionary > Melanosome

Melanosome

Definition
noun, plural: melanosomes
An organelle in pigment cell that synthesizes and stores melanin
Supplement
A melanosome is an organelle of a pigment cell, such as a melanocyte. A melanocyte is a pigment cell that produces melanin, a natural pigment responsible for the color of skin, hair, eyes, etc. Melanin is synthesized and stored within the melanosome. Melanogenesis is the process of producing melanin. Producing melanin is important since it is a means of the body to protect the underlying skin layer such as the hypodermis from adverse effects (e.g. DNA photodamage) of UV-B light exposure. The black (or dark brown) pigment allows the absorption of the majority of the UV-B light passing through the skin layer.1 Thus, increased exposure to UV-B radiation leads to heightened melanogenesis.
Melanosomes are elongated organelles and resemble sausage or cigar in shape. They may reach up to 500 nm in length. The organelle is bounded by a bilipid membrane. Some melanosomes are capable of movement within the melanocyte. They do so by forming pseudopodia that aid in their movement within the cell in response to UV light (photoprotective function).
Word origin: Greek melas (“black, dark”)
See also:

Reference(s):

1 Agar, N. & Young, A. R. (2005). “Melanogenesis: a photoprotective response to DNA damage?”. Mutation Research. 571 (1–2): 121–32.


You will also like...

Energy pyramid
Freshwater Community Energy Relationships – Producers & Consumers

This tutorial looks at the relationship between organisms. It also explores how energy is passed on in the food chain an..

Thermographic image of face and neck
Regulation of Organic Metabolism, Growth and Energy Balance

The human body is capable of regulating growth and energy balance through various feedback mechanisms. Get to know the e..

IQ, Creativity and Learning
IQ, Creativity and Learning

Human intelligence provided the means to utilize abstract ideas and implement reasoning. This tutorial takes a further l..

Population Regulation in an Ecosystem
Population Regulation in an Ecosystem

With regard to the population size of a species and what factors may affect them, two factors have been defined. They ar..

squirrel
Animal Water Regulation

Animals adapt to their environment in aspects of anatomy, physiology, and behavior. This tutorial will help you understa..

Lentic community
Freshwater Communities & Lentic Waters

Lentic or still water communities can vary greatly in appearance -- from a small temporary puddle to a large lake. The s..