So, in this case, we're just drawing the molecular orbital diagram for the valence electrons, so we have three for each.

所以在这个例子里面，我们只需要画出,价电子的分子轨道图，所以每个有3个电子。

麻省理工公开课 - 化学原理课程节选

These are the pentoses - remember 5' and 3' because that orients you with respect to what direction the molecule is facing.

这些就是戊糖,记住了5'碳和3'碳就能够,帮你确定分子的方向

耶鲁公开课 - 生物医学工程探索课程节选

You know that these molecules are also linked in another way, by the phosphate bonds that connect the 3 and the 5 carbons of adjacent nucleotides.

这些分子还通过别的方式连接在一起,例如通过相邻核苷酸的3碳位和,5碳位之间的磷酸键相连

耶鲁公开课 - 生物医学工程探索课程节选