Justify: Sugars are connected by phosphodiester bonds?
In nucleic acids Sugar Back bones are connected with Phosphodiester bonds.
IN simple terms -OH attached to the 3' C in the sugar backbone of the nucleic acid is available for nucleophilic attack by another incoming base phosphate group which removes diphosphate as a by product and then forms a diester bond between the 3' C of sugar with the incoming Bases phosphate group.
Following is a mechanism for the same
[where base is attached is C-1' and then move away from O, so -OH comes to be on C-3']
here the 3' C -OH group attacks the P of the Phosphate group nearest to the sugar and releases di Phosphate group and forming a diester bond where Phosphorus is at center and thus it is called Phosphodiester bond.