Melanosomes are organelles found in the skin, eyes and inner ear. They are responsible for producing and storing melanin, the pigment that gives color to these tissues. Melanin is produced by the enzyme tyrosinase, which is located in the melanosomes. The amount of melanin produced by each melanocyte (the cell that produces melanin) varies depending on its activity level. For example, during a tanning response, melanocytes increase their activity and produce more melanin.
The main function of melanin is to protect the body from harmful UV rays emitted by the sun. It does this by absorbing UV radiation and converting it into heat, which helps to prevent DNA damage that can lead to skin cancer. Melanin also plays a role in protecting the eyes from damage caused by exposure to sunlight. In addition, it helps to absorb light in low-light conditions, which makes it possible for us to see at night.
There are two types of melatonin: eumelanin and pheomelanin. Eumelanin is darker in color and provides better protection against UV radiation than pheomelanin. Pheomelanins are usually only found in small amounts in human skin but they can be increased during a tanning response. People with higher levels of eumelanins tend to have darker skin colors while those with higher levels of pheomelanins tend to have lighter skin colors.