Retinol is a primary alcohol containing:-
Retinol (vitamin A alcohol): 

lt is a primary alcohol containing beta-ionone ring. 
The side chain has two isoprenoid units, four double bonds and one hydroxyl group. 
Retinol is present in animal tissues as retinyl ester with long chain fatty acids

Key Concept:
Retinol is a vitamin A (alcohol containing beta-ionone ring)
Alpha-ionone ring
Beta-ionone ring
One isoprenoid unit
Two double bonds