This is a feature of DNA shown in this cartoon form, so if you can keep that sort of schematic in mind, it makes it a lot easier to understand the detailed structure.

这是卡通模型所表现的DNA的特点之一,如果你能把这个模型记住,你会很容易理解DNA分子的详细结构

耶鲁公开课 - 生物医学工程探索课程节选