Each nucleotide consists of a ribose sugar, phosphate group and nucleotide base.

每个核苷酸由核糖、磷酸基团和核苷酸碱组成。

Think of DNA's structure as a ladder whose rungs are made up of different bases and sides as sugar – phosphate.

把 DNA 的结构想象成一个梯子，阶梯是由不同的碱基组成的，两边是糖-磷酸。