Provided are novel nucleotides, nucleoside, and their derivatives described herein, that can be used in DNA sequencing technology and other types of DNA analysis. In one embodiment, the nucleotide or nucleoside with an unprotected 3'-OH group is derivatized at the nucleobase to include a fluorescent dye attached via a linker to a photocleavable terminating group. The photocleavable-fluorescent group is designed to terminate DNA synthesis as well as be cleaved so that DNA oligomers can be sequenced efficiently in a parallel format. The design of such rapidly cleavable fluorescent groups on nucleotides and nucleosides can enhance the speed and accuracy of sequencing of large oligomers of DNA in parallel, to allow rapid whole genome sequencing, and the identification of polymorphisms and other valuable genetic information, as well as allowing further manipulation and analysis of nucleic acid molecules in their native state following cleavage of the fluorescent group.