It's the phosphate and the pentose that make up the backbone - that make up the upright struts of the ladder and it's the bases that make up the connecting struts, so the bases are the colors.

磷酸基和戊糖,共同构成了主链,主链又构成了梯子上下的支柱,而碱基,则构成连接支柱的梯阶,碱基是用各种颜色表示的

耶鲁公开课 - 生物医学工程探索课程节选

And the dialogue ends with one of the great moving death scenes in western civilization and as Plato says-- let's get the quote here exactly right-- "Of all those we have known, he was the best and also the wisest and the most upright."

然后对话以一个,西方文明史上最伟大感人的死亡场景结束,用柏拉图的话说,让我们引用的更准确些,在我们所知的所有人中,他是最好,最有智慧,最正直的人

耶鲁公开课 - 死亡课程节选

Now DNA is a double helix and I've only shown you one part of the helix, right? I've shown you one upright strut and a base hanging off of it, but it forms a double helix because complementary strands of DNA strongly associate with one another and that's a very stable structure.

NA是双螺旋,我只是给你们讲了螺旋的一边,我给你们演示,一条链的支柱及碱基团,但其能构成双螺旋,是因为DNA是完全互补的两条链,彼此之间结合紧密,结构异常稳定

耶鲁公开课 - 生物医学工程探索课程节选