Carotene

Carotene is an orange photosynthetic pigment, important for photosynthesis.

It is responsible for the orange colour of the carrot, and can cause people who have consumed enough to turn slightly yellow. It does not actively contribute in photosynthesis, but instead it transmits the energy it absorbs to chlorophyll.

Carotene is the dimer of vitamin A and comes in two forms α and β-carotene. Both types can be stored in the liver, and unlike vitamin A, excess carotene is non-toxic and can also be converted to vitamin A as needed.

External link(s)

http://www.chm.bris.ac.uk/motm/carotene/beta-carotene_home.html