Carotenoids general chemical structure as represented by Beta-carotene;
yellow-orange pigment in carrots
or Alpha-carotene 
Only difference is position of one double bond, can you find it?
Other examples ;
Lycopene
red pigment in tomattos
Lutein
yellow pigment in merigolds.
Zeaxanthin
near twin of lutein.
In fact you could call zeaxanthin Alpha-lutein, because lutein is to Beta-carotene
as zeaxanthin is to Alpha-carotene.