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...

Kidneys
Kidneys and Regulation of Water and Inorganic Ions

The kidneys are responsible for the regulation of water and inorganic ions. Read this tutorial to learn about the differ..

Plant Auxins
Plant Auxins – Phototropism & Geotropism

Plants produce hormones to regulate their growth. Auxins, for instance, influence plant growth. Know the role of auxin i..

DNA molecule
Genetic Control – On and Off Genes

Genes are the blueprint of our bodies, a blueprint that creates a variety of proteins essential to any organism's surviv..

Photosynthesis and respiration
Plant Metabolism

Plants are responsible for incredible feats of molecular transformation. Plant processes, such as photosynthesis, photop..

Consciousness and behavior
Consciousness and Behavior

Human consciousness and behavior are an interesting topic since they are determined and controlled by the brain. Conscio..

Biological Cell Defense
Biological Cell Defense

Organisms employ different strategies to boost its defenses against antigens. Humans have an immune system to combat pat..

Related Articles...

No related articles found

See all Related Topics