Nucleoside

A nucleoside combines a nucleobase with a sugar, without the phosphate groups of a nucleotide. Adenosine is the nucleoside built from adenine and ribose. See Alberts et al., Molecular Biology of the Cell: nucleosides and nucleotides.

A brominated thymidine analogue incorporated during DNA synthesis. Substitution changes buoyant density, allowing copied strands to be distinguished from unsubstituted strands.

Inosine is the ribonucleoside of hypoxanthine. Hydrolytic deamination of adenosine replaces its exocyclic amino group with a carbonyl oxygen while retaining its sugar attachment.

Adenosine consists of adenine joined to ribose. Adding one, two, or three phosphate groups at the ribose's $5^{\prime }$ position gives AMP, ADP, or ATP, respectively. See Alberts et al., Molecular Biology of the Cell: the components of nucleotides.